Take shallow copy snapshot only when remote store compatibility mode is STRICT

[ltaragi]

Description

• This change ensures that when under remote-store/docrep migration, shallow snapshots are not taken as both remote-backed and non-remote-backed indices are present.
• For the createSnapshot operation, if the remote_store_index_shallow_copy setting is found to be true in the repository metadata settings but the cluster is in the MIXED compatibility mode, we override this setting to false. Thus, we do not honor the shallow snapshot setting and create full snapshots only.

Related Issues

Resolves #13101

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)
• Public documentation issue/PR created

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[github-actions]

✅ Gradle check result for 1e351a9: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 71.53%. Comparing base (b15cb0c) to head (aa7df1a).
Report is 214 commits behind head on main.

❗ Current head aa7df1a differs from pull request most recent head 6981075. Consider uploading reports for the commit 6981075 to get more accurate results

Files	Patch %	Lines
...ava/org/opensearch/snapshots/SnapshotsService.java	40.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #13309      +/-   ##
============================================
+ Coverage     71.42%   71.53%   +0.11%     
- Complexity    59978    60777     +799     
============================================
  Files          4985     5044      +59     
  Lines        282275   285683    +3408     
  Branches      40946    41369     +423     
============================================
+ Hits         201603   204365    +2762     
- Misses        63999    64469     +470     
- Partials      16673    16849     +176     

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[github-actions]

❌ Gradle check result for 228bef4: 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?

[ltaragi]

❌ Gradle check result for 228bef4: 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?

org.opensearch.indices.IndicesRequestCacheIT.testProfileDisableCache {p0={"search.concurrent_segment_search.enabled":"true"}}

Flaky test #11374

[github-actions]

✅ Gradle check result for aa7df1a: SUCCESS

[github-actions]

✅ Gradle check result for 6981075: SUCCESS