Changing checksum setting to support modes

[himshikha]

Description

This changes the checksum validation setting for remote cluster state to use different modes rather than just enable/disable. Modes added:

1. None: Validation will be disabled.
2. Debug: Validation enabled but only matches checksum and logs failing entities.
3. Trace: Matches checksum and downloads full cluster state to find diff in failing entities. Only logs failures.
4. Failure: Throws exception on failing validation.

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.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[github-actions]

❌ Gradle check result for a4c250e: 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?

[himshikha]

❌ Gradle check result for a4c250e: 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?

Flaky test #14302, #14294, #14289

[github-actions]

❌ Gradle check result for 2c66491: 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?

[himshikha]

❌ Gradle check result for 2c66491: 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?

Flaky test #14294

[github-actions]

❕ Gradle check result for 3ad0979: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.http.SearchRestCancellationIT.testAutomaticCancellationDuringFetchPhase
      1 org.opensearch.cluster.MinimumClusterManagerNodesIT.testThreeNodesNoClusterManagerBlock
      1 org.opensearch.backwards.MixedClusterClientYamlTestSuiteIT.test {p0=snapshot.status/10_basic/Get missing snapshot status succeeds when ignoreUnavailable is true}

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 85.29412% with 5 lines in your changes missing coverage. Please review.

Project coverage is 71.87%. Comparing base (a60b668) to head (3ad0979).
Report is 16 commits behind head on main.

Files with missing lines	Patch %	Lines
...arch/gateway/remote/RemoteClusterStateService.java	85.29%	3 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #15622      +/-   ##
============================================
- Coverage     71.93%   71.87%   -0.07%     
- Complexity    63995    64011      +16     
============================================
  Files          5259     5259              
  Lines        299435   299454      +19     
  Branches      43270    43275       +5     
============================================
- Hits         215412   215237     -175     
- Misses        66287    66466     +179     
- Partials      17736    17751      +15     

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[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-15622-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 a608fcaefbf046fbc9f177907a14130d769cadda
# Push it to GitHub
git push --set-upstream origin backport/backport-15622-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-15622-to-2.x.