Allow deprecation warning for API call 'GET _cat/master' in 'ExceptionIT' of mixed cluster BWC test

[tlfeng]

Description

• Allow deprecation warning when calling GET _cat/master API in ExceptionIT class of mixed cluster BWC test

The test ExceptionIT.testOpensearchException() calls API GET _cat/master to log the cluster-manager node ID.
Since the REST API is deprecated in version 2.0 and RestClient used in the test treats warning as failure, the test breaks when running the BWC test against node version >=2.0

Note:
Mixed cluster BWC test will spin up 4 nodes with the specified old version, and upgrade 2 nodes to the current version to form a mixed version cluster.

Issues Resolved

Resolve #2759

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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.

[opensearch-ci-bot]

✅   Gradle Check success b3c0929
Log 4190

Reports 4190

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-2.x 2.x
# Navigate to the new working tree
cd .worktrees/backport-2.x
# Create a new branch
git switch --create backport/backport-2767-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 249155772b65681ba8e91d2356e3430f2236b6be
# Push it to GitHub
git push --set-upstream origin backport/backport-2767-to-2.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-2767-to-2.x.