Implemented computation of segment replication stats at shard level

[vinaykpud]

Description

The method implemented here computes the segment replication stats at the shard level, instead of relying on the primary shard to compute stats based on reports from its replicas.

Method implemented in this PR serves the segment replication stats for following core APIs:

1. Nodes Stats API (/_nodes/stats)
2. Cluster Stats API (/_cluster/stats)
3. Indices Stats API (/_stats or /{index}/_stats)

Related Issues

Resolves #16801
Related to #15306

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 6ee1808: 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 4e2b335: SUCCESS

[github-actions]

❌ Gradle check result for 04ba008: 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 3d030d5: SUCCESS

[mch2]

@vinaykpud Thanks for pushing on this, I think this is really close.

[github-actions]

❌ Gradle check result for 25fd006: 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 d8585f7: 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 d8585f7: 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.

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/OpenSearch/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/OpenSearch/backport-2.x
# Create a new branch
git switch --create backport/backport-17055-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 ee7fbbd226b2be81128eaafe19aad0a39244368c
# Push it to GitHub
git push --set-upstream origin backport/backport-17055-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/OpenSearch/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-17055-to-2.x.

[mch2]

ignoring backport here, this is a 3.0 only change.