[Backport 2.x] Introduce remote store path type in customData in IndexMetadata (#12607)

[ashking94]

Backport 91582e7 from #12607.

[github-actions]

❕ Gradle check result for a1f88b8: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.backwards.MixedClusterClientYamlTestSuiteIT.test {p0=indices.get_field_mapping/20_missing_field/Return empty object if field doesn't exist, but index does}

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 88.46154% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 71.07%. Comparing base (0dd892c) to head (a1f88b8).
Report is 182 commits behind head on 2.x.

Files	Patch %	Lines
...g/opensearch/index/remote/RemoteStorePathType.java	66.66%	2 Missing ⚠️
...h/cluster/metadata/MetadataCreateIndexService.java	92.85%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x   #13390      +/-   ##
============================================
- Coverage     71.28%   71.07%   -0.22%     
- Complexity    60145    60691     +546     
============================================
  Files          4957     5013      +56     
  Lines        282799   285897    +3098     
  Branches      41409    41784     +375     
============================================
+ Hits         201591   203191    +1600     
- Misses        64189    65587    +1398     
- Partials      17019    17119     +100     

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[github-actions]

✅ Gradle check result for afcb335: SUCCESS