Support API hint for per-instrument temporality selection

[jmacd]

Description: Support an API hint for controlling temporality. This is needed for Lightstep internally to support its current synchronous Gauge workaround combined with ordinary OTel UpDownCounter instruments since we need different temporality settings for these two use-cases (i.e., delta Gauges and cumulative UpDownCounters).

Link to tracking Issue: Part of https://lightstep.atlassian.net/browse/LS-45763.

Testing: An existing API-Hint test was extended to cover the new setting.

Documentation: ✅

[codecov-commenter]

Codecov Report

Patch coverage: 75.86% and project coverage change: -0.10 ⚠️

Comparison is base (1d4b504) 87.87% compared to head (a094354) 87.78%.

❗ Current head a094354 differs from pull request most recent head d7e34a7. Consider uploading reports for the commit d7e34a7 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #426      +/-   ##
==========================================
- Coverage   87.87%   87.78%   -0.10%     
==========================================
  Files          75       74       -1     
  Lines        4288     4305      +17     
==========================================
+ Hits         3768     3779      +11     
- Misses        445      449       +4     
- Partials       75       77       +2     

Impacted Files	Coverage Δ
...p/sdk/metric/aggregator/aggregation/temporality.go	65.21% <71.42%> (+9.66%)	⬆️
...ghtstep/sdk/metric/internal/viewstate/viewstate.go	97.69% <80.00%> (-0.96%)	⬇️

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[moh-osman3]

LGTM! Thanks for making this change!

[paivagustavo]

LGTM