Add tests for RemoteGlobalMetadataManager

[shiv0408]

Description

Add tests for async read and write of attributes in RemoteGlobalMetadataManager. These flows were added in #14089, #13924 but coverage for these flows were not sufficient.

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

❕ Gradle check result for c0a12f2: UNSTABLE

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

All modified and coverable lines are covered by tests ✅

Project coverage is 71.77%. Comparing base (b15cb0c) to head (b456243).
Report is 453 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #14394      +/-   ##
============================================
+ Coverage     71.42%   71.77%   +0.35%     
- Complexity    59978    62099    +2121     
============================================
  Files          4985     5118     +133     
  Lines        282275   291833    +9558     
  Branches      40946    42180    +1234     
============================================
+ Hits         201603   209456    +7853     
- Misses        63999    65066    +1067     
- Partials      16673    17311     +638     

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[github-actions]

❌ Gradle check result for 587c566: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[shiv0408]

❌ Gradle check result for 3aefbed: FAILURE

org.opensearch.upgrades.IndexingIT.testIndexingWithSegRep - #14302

[github-actions]

✅ Gradle check result for ec042aa: SUCCESS

[github-actions]

❌ Gradle check result for 5924b92: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[shiv0408]

❌ Gradle check result for 5924b92: FAILURE

org.opensearch.action.admin.indices.create.RemoteCloneIndexIT.testCreateCloneIndexFailure - #14292
org.opensearch.search.SearchTimeoutIT.testSimpleTimeout {p0={"search.concurrent_segment_search.enabled":"true"}} - #9401

[github-actions]

❌ Gradle check result for b456243: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❕ Gradle check result for b456243: UNSTABLE

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.