feat: remove old model usage from sampling package

[kruskall]

Motivation/summary

Small fix that can be reviewed in parallel with the rest of the protobuf work

Checklist

• Update CHANGELOG.asciidoc
• Update package changelog.yml (only if changes to apmpackage have been made)
• Documentation has been updated

For functional changes, consider:

• Is it observable through the addition of either logging or metrics?
• Is its use being published in telemetry to enable product improvement?
• Have system tests been added to avoid regression?

How to test these changes

Related issues

Related to elastic/apm-data#52

[mergify]

This pull request does not have a backport label. Could you fix it @kruskall? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-7.x is the label to automatically backport to the 7.x branch.
• backport-7./d is the label to automatically backport to the 7./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[apmmachine]

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• Start Time: 2023-06-15T08:24:54.600+0000

• Duration: 20 min 20 sec

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[apmmachine]

📚 Go benchmark report

Diff with the main branch

goos: linux
goarch: amd64
pkg: github.com/elastic/apm-server/internal/agentcfg
cpu: 12th Gen Intel(R) Core(TM) i5-12500
                                  │ build/main/bench.out │             bench.out             │
                                  │        sec/op        │   sec/op     vs base              │
geomean                                      67.79n        67.50n       -0.43%

                                  │ build/main/bench.out │             bench.out              │
                                  │         B/op         │    B/op     vs base                │
geomean                                                ²               +0.00%               ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                                  │ build/main/bench.out │             bench.out              │
                                  │      allocs/op       │ allocs/op   vs base                │
geomean                                                ²               +0.00%               ²
¹ all samples are equal
² summaries must be >0 to compute geomean

pkg: github.com/elastic/apm-server/internal/beater/request
                                             │ build/main/bench.out │             bench.out              │
                                             │        sec/op        │    sec/op     vs base              │
geomean                                                907.6n         887.8n        -2.18%

                                             │ build/main/bench.out │              bench.out               │
                                             │         B/op         │     B/op      vs base                │
geomean                                                           ²                 +0.00%               ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                                             │ build/main/bench.out │             bench.out              │
                                             │      allocs/op       │ allocs/op   vs base                │
geomean                                                           ²               +0.00%               ²
¹ all samples are equal
² summaries must be >0 to compute geomean

pkg: github.com/elastic/apm-server/internal/publish
             │ build/main/bench.out │          bench.out          │
             │        sec/op        │   sec/op    vs base         │

             │ build/main/bench.out │           bench.out            │
             │         B/op         │     B/op       vs base         │

             │ build/main/bench.out │           bench.out           │
             │      allocs/op       │  allocs/op    vs base         │

pkg: github.com/elastic/apm-server/x-pack/apm-server/aggregation/spanmetrics
                 │ build/main/bench.out │           bench.out           │
                 │        sec/op        │    sec/op     vs base         │

                 │ build/main/bench.out │            bench.out            │
                 │         B/op         │     B/op      vs base           │
¹ all samples are equal

                 │ build/main/bench.out │           bench.out           │
                 │      allocs/op       │ allocs/op   vs base           │
¹ all samples are equal

pkg: github.com/elastic/apm-server/x-pack/apm-server/aggregation/txmetrics
                        │ build/main/bench.out │          bench.out           │
                        │        sec/op        │   sec/op     vs base         │

                        │ build/main/bench.out │           bench.out           │
                        │         B/op         │    B/op     vs base           │
¹ all samples are equal

                        │ build/main/bench.out │           bench.out           │
                        │      allocs/op       │ allocs/op   vs base           │
¹ all samples are equal

pkg: github.com/elastic/apm-server/x-pack/apm-server/sampling
               │ build/main/bench.out │             bench.out              │
               │        sec/op        │    sec/op     vs base              │
geomean                  428.5n         399.6n        -6.75%

               │ build/main/bench.out │              bench.out               │
               │         B/op         │     B/op      vs base                │
geomean                    378.2          376.3       -0.53%
¹ all samples are equal

               │ build/main/bench.out │             bench.out              │
               │      allocs/op       │ allocs/op   vs base                │
geomean                    4.123        4.123       +0.00%
¹ all samples are equal

pkg: github.com/elastic/apm-server/x-pack/apm-server/sampling/eventstorage
                                            │ build/main/bench.out │               bench.out               │
                                            │        sec/op        │     sec/op      vs base               │
ReadEvents/nop_codec_big_tx/399_events-12             422.5µ ± 15%    377.1µ ±  17%  -10.73% (p=0.015 n=6)
ReadEvents/nop_codec_big_tx/1000_events-12            702.1µ ± 20%    641.5µ ±  13%   -8.63% (p=0.026 n=6)
geomean                                               17.08µ          16.58µ          -2.94%

                                            │ build/main/bench.out │               bench.out               │
                                            │         B/op         │     B/op       vs base                │
ReadEvents/nop_codec_big_tx/399_events-12            195.5Ki ±  1%   194.9Ki ±  1%  -0.29% (p=0.028 n=6)
geomean                                              11.98Ki         11.99Ki        +0.10%
¹ all samples are equal

                                            │ build/main/bench.out │              bench.out              │
                                            │      allocs/op       │  allocs/op   vs base                │
geomean                                                 127.7         127.7       +0.00%
¹ all samples are equal

report generated with https://pkg.go.dev/golang.org/x/perf/cmd/benchstat