Introduce execution_hint for Cardinality aggregation (#17312) - backport to 2.x

[asimmahmood1]

Description

[Describe what this change achieves]
Backport #17312 to 2.x

Backport to 2.19 is already done: https://github.com/opensearch-project/OpenSearch/pull/17420/files

Also need to backport the documentation opensearch-project/documentation-website#9224

Related Issues

Resolves #[16837]

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 90a7bc8: 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?

[peterzhuamazon]

Convert this back to draft until further notice.
To understand if it will break anything in 2.19.1.

Thanks.

[github-actions]

❌ Gradle check result for a11eb0e: 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 668018b: 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 668018b: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 77.41935% with 7 lines in your changes missing coverage. Please review.

Project coverage is 71.98%. Comparing base (6a05e73) to head (668018b).
Report is 5 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...gations/metrics/CardinalityAggregationBuilder.java	66.66%	1 Missing and 4 partials ⚠️
...egations/metrics/CardinalityAggregatorFactory.java	80.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x   #17419      +/-   ##
============================================
+ Coverage     71.95%   71.98%   +0.03%     
- Complexity    65944    65967      +23     
============================================
  Files          5341     5341              
  Lines        307186   307210      +24     
  Branches      44830    44837       +7     
============================================
+ Hits         221026   221156     +130     
+ Misses        67703    67638      -65     
+ Partials      18457    18416      -41     

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