Fix testUploadMetadataMissingSegment unit test on 2.x

[dreamer-89]

Description

Fixes unit test testUploadMetadataMissingSegment by fetching primary term from ReplicationCheckpoint vs using hard-coded value.

Related Issues

Resolves #9096

Test

Ran this test 1k times successfully without failure

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)

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[opensearch-trigger-bot]

Compatibility status:

> Task :checkCompatibility
Checking compatibility for: https://github.com/opensearch-project/opensearch-oci-object-storage.git with ref: 2.x
Skipping compatibility check for https://github.com/opensearch-project/opensearch-oci-object-storage.git
Incompatible components: [https://github.com/opensearch-project/alerting.git, https://github.com/opensearch-project/anomaly-detection.git, https://github.com/opensearch-project/index-management.git, https://github.com/opensearch-project/k-nn.git, https://github.com/opensearch-project/geospatial.git, https://github.com/opensearch-project/cross-cluster-replication.git, https://github.com/opensearch-project/notifications.git, https://github.com/opensearch-project/ml-commons.git]
Components skipped due to git failures: [https://github.com/opensearch-project/opensearch-oci-object-storage.git]
Compatible components: [https://github.com/opensearch-project/security.git, https://github.com/opensearch-project/asynchronous-search.git, https://github.com/opensearch-project/job-scheduler.git, https://github.com/opensearch-project/common-utils.git, https://github.com/opensearch-project/sql.git, https://github.com/opensearch-project/reporting.git, https://github.com/opensearch-project/observability.git, https://github.com/opensearch-project/neural-search.git, https://github.com/opensearch-project/performance-analyzer.git, https://github.com/opensearch-project/performance-analyzer-rca.git, https://github.com/opensearch-project/security-analytics.git]

BUILD SUCCESSFUL in 23m 19s

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      1 org.opensearch.indices.replication.SegmentReplicationRelocationIT.testRelocateWhileContinuouslyIndexingAndWaitingForRefresh

• URL: https://build.ci.opensearch.org/job/gradle-check/21820/
• CommitID: 17cc4b4
  Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Merging #9099 (17cc4b4) into 2.x (6ab46bd) will increase coverage by 0.12%.
Report is 3 commits behind head on 2.x.
The diff coverage is 95.65%.

@@             Coverage Diff              @@
##                2.x    #9099      +/-   ##
============================================
+ Coverage     70.72%   70.84%   +0.12%     
- Complexity    57372    57473     +101     
============================================
  Files          4754     4754              
  Lines        271625   271650      +25     
  Branches      40066    40067       +1     
============================================
+ Hits         192102   192460     +358     
+ Misses        62972    62705     -267     
+ Partials      16551    16485      -66     

Files Changed	Coverage Δ
...ch/indices/recovery/PeerRecoveryTargetService.java	51.96% <0.00%> (-1.97%)	⬇️
...nsearch/search/internal/FilteredSearchContext.java	8.84% <0.00%> (-0.08%)	⬇️
...va/org/opensearch/search/DefaultSearchContext.java	78.84% <90.00%> (+0.55%)	⬆️
...ices/replication/RemoteStoreReplicationSource.java	90.74% <96.42%> (-3.55%)	⬇️
...in/java/org/opensearch/index/shard/IndexShard.java	69.01% <100.00%> (-0.70%)	⬇️
...search/index/shard/RemoteStoreRefreshListener.java	84.06% <100.00%> (-0.64%)	⬇️
...java/org/opensearch/index/shard/StoreRecovery.java	56.72% <100.00%> (-0.53%)	⬇️
...earch/index/store/RemoteSegmentStoreDirectory.java	87.70% <100.00%> (ø)
...rc/main/java/org/opensearch/index/store/Store.java	80.10% <100.00%> (-0.14%)	⬇️
...x/store/remote/metadata/RemoteSegmentMetadata.java	100.00% <100.00%> (ø)
... and 2 more

... and 466 files with indirect coverage changes