Add remote to local pool change handling in TargetPoolAllocationDecider

[skumawat2025]

This PR adds following changes.

• Changes in TargetPoolAllocationDecider - If shards exists in REMOTE_POOL node and shard pool changes for these shards. Decider should make sure these can no longer remain on the REMOTE_POOL nodes.
• Changed INDEX_STORE_LOCALITY_SETTING setting occurrences to IS_WARM_INDEX setting

Description

[Describe what this change achieves]

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

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 085f06d: 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?

[rayshrey]

We have some tests failing which seem related to the current changes only, can you check and fix these failures - https://build.ci.opensearch.org/job/gradle-check/56866/

[skumawat2025]

We have some tests failing which seem related to the current changes only, can you check and fix these failures - https://build.ci.opensearch.org/job/gradle-check/56866/

Fixed.

[github-actions]

❕ Gradle check result for 4887d36: 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

Attention: Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.

Project coverage is 72.55%. Comparing base (96481cc) to head (4887d36).
Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
...g/opensearch/cluster/routing/OperationRouting.java	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #18027      +/-   ##
============================================
- Coverage     72.59%   72.55%   -0.04%     
+ Complexity    67172    67127      -45     
============================================
  Files          5478     5478              
  Lines        310125   310131       +6     
  Branches      45080    45082       +2     
============================================
- Hits         225135   225021     -114     
- Misses        66676    66712      +36     
- Partials      18314    18398      +84     

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[rayshrey]

LGTM