[Backport 2.x] Add search backpressure service check for query group tasks

[opensearch-trigger-bot]

Backport 8ee5eeb from #17576.

[github-actions]

❌ Gradle check result for 9151b5f: 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 9151b5f: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.gateway.RecoveryFromGatewayIT.testShardStoreFetchMultiNodeMultiIndexesUsingBatchAction

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 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 71.98%. Comparing base (4cfa376) to head (9151b5f).
Report is 9 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...ain/java/org/opensearch/wlm/QueryGroupService.java	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x   #17591      +/-   ##
============================================
- Coverage     72.13%   71.98%   -0.15%     
+ Complexity    66109    65999     -110     
============================================
  Files          5342     5342              
  Lines        307285   307289       +4     
  Branches      44847    44848       +1     
============================================
- Hits         221666   221215     -451     
- Misses        67142    67588     +446     
- Partials      18477    18486       +9     

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