Delegate to NettyAllocator.getAllocator() for ByteBufAllocator instead of hard-coding PooledByteBufAllocator.

[vrozov]

opensearch-security pull request intake form

Please provide as much details as possible to get feedback/acceptance on your PR quickly

1. Category: (Enhancement, New feature, Bug fix, Test fix, Refactoring, Maintenance, Documentation)
   Enhancement

2. Github Issue # or road-map entry, if available:

3. Description of changes:
   security plugin should rely on NettyAllocator.getAllocator() to get ByteBufAllocator based on configured settings and parameters. Hard-coding DEFAULT PooledByteBufAllocator may cause unexpected allocator to be used.

4. Why these changes are required?

5. What is the old behavior before changes and new behavior after changes? (Please add any example/logs/screen-shot if available)

6. Testing done: (Please provide details of testing done: Unit testing, integration testing and manual testing)

7. TO-DOs, if any: (Please describe pending items and provide Github issues# for each of them)

8. Is it backport from main branch? (If yes, please add backport PR # and commits #)

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[codecov-commenter]

Codecov Report

Merging #1396 (2b41670) into main (ce59944) will not change coverage.
The diff coverage is 75.00%.

@@            Coverage Diff            @@
##               main    #1396   +/-   ##
=========================================
  Coverage     60.93%   60.93%           
+ Complexity     3225     3224    -1     
=========================================
  Files           256      256           
  Lines         18048    18048           
  Branches       3221     3221           
=========================================
  Hits          10998    10998           
  Misses         5469     5469           
  Partials       1581     1581           

Impacted Files	Coverage Δ
...ensearch/security/ssl/DefaultSecurityKeyStore.java	67.63% <75.00%> (ø)
...security/auditlog/sink/ExternalOpenSearchSink.java	59.25% <0.00%> (-2.47%)	⬇️
...a/org/opensearch/security/tools/SecurityAdmin.java	37.56% <0.00%> (+0.24%)	⬆️

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[peternied]

@vrozov This change looks valuable for being consistent in our shared resource usage patterns. How would you feel about rebasing and getting this merged?

[peternied]

I've rebased and will shepherd this pull request. @opensearch-project/security could we get another review?