Remote routing input stream read

[Arpit-Bandejiya]

Description

This PR completes the #13577 flow end to end. The main changes done in this file are in:

server/src/main/java/org/opensearch/gateway/remote/routingtable/IndexRoutingTableInputStreamReader.java

I have also added one basic test in the PR for validation of the flow.

Related Issues

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

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 270e00d: 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?