[Backport] [2.x] [Concurrent Segment Search]: Implement concurrent aggregations support without profile option

[sohami]

Description

• Backport of [Concurrent Segment Search]: Implement concurrent aggregations support without profile option #7514 to 2.x branch
• Address serializing pipelineTree in QueryResult in 2.x for bwc and fix the new tests as well. Pipeline Tree is deprecated in main branch

Related Issues

Resolves #7353

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
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)

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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/17008/
• CommitID: c656ef4
  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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/17089/
• CommitID: dc2c076
  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 (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      1 org.opensearch.search.pit.DeletePitMultiNodeIT.testDeleteWhileSearch
      1 org.opensearch.search.SearchWeightedRoutingIT.testStrictWeightedRoutingWithCustomString
      1 org.opensearch.cluster.allocation.AwarenessAllocationIT.testThreeZoneOneReplicaWithForceZoneValueAndLoadAwareness

• URL: https://build.ci.opensearch.org/job/gradle-check/17088/
• CommitID: f89200e
  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

Merging #7948 (f4572f2) into 2.x (740956a) will decrease coverage by 0.03%.
The diff coverage is 73.99%.

@@             Coverage Diff              @@
##                2.x    #7948      +/-   ##
============================================
- Coverage     70.59%   70.57%   -0.03%     
- Complexity    56485    56521      +36     
============================================
  Files          4673     4681       +8     
  Lines        267919   268039     +120     
  Branches      39646    39655       +9     
============================================
+ Hits         189149   189170      +21     
- Misses        62452    62589     +137     
+ Partials      16318    16280      -38     

Impacted Files	Coverage Δ
...pensearch/action/search/TransportSearchAction.java	70.99% <0.00%> (-0.22%)	⬇️
...search/aggregations/SearchContextAggregations.java	100.00% <ø> (ø)
...nsearch/search/internal/FilteredSearchContext.java	9.17% <0.00%> (-0.09%)	⬇️
.../org/opensearch/search/internal/SearchContext.java	37.20% <ø> (ø)
...main/java/org/opensearch/search/SearchService.java	71.71% <25.00%> (ø)
...arch/aggregations/DefaultAggregationProcessor.java	48.78% <48.78%> (ø)
...va/org/opensearch/search/DefaultSearchContext.java	78.68% <50.00%> (-0.24%)	⬇️
...h/aggregations/ConcurrentAggregationProcessor.java	70.00% <70.00%> (ø)
.../GlobalAggCollectorManagerWithSingleCollector.java	71.42% <71.42%> (ø)
...arch/aggregations/AggregationCollectorManager.java	73.33% <73.33%> (ø)
... and 15 more

... and 454 files with indirect coverage changes

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/17094/
• CommitID: f4572f2