Fix Netty's ByteBuf leak

[reta]

Description

Fix Netty's ByteBuf leak

java.lang.AssertionError: 
Expected: an empty collection
     but: <[LEAK: ByteBuf.release() was not called before it's garbage-collected. See https://netty.io/wiki/reference-counted-objects.html for more information.
Recent access records: 
#1:
	org.opensearch.http.reactor.netty4.ReactorNetty4StreamingRequestConsumer.createChunk(ReactorNetty4StreamingRequestConsumer.java:47)
	org.opensearch.http.reactor.netty4.ReactorNetty4StreamingRequestConsumer.accept(ReactorNetty4StreamingRequestConsumer.java:37)
	org.opensearch.http.reactor.netty4.ReactorNetty4StreamingRequestConsumer.accept(ReactorNetty4StreamingRequestConsumer.java:23)

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[reta]

@andrross please when you have time, thanks (and apologies for that)

[github-actions]

❌ Gradle check result for 0e0df64: 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 0e0df64: SUCCESS

[github-actions]

✅ Gradle check result for 4555934: SUCCESS

[github-actions]

✅ Gradle check result for 77dcf7c: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.

Project coverage is 71.93%. Comparing base (b30df02) to head (77dcf7c).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...ch/http/reactor/netty4/ReactorNetty4HttpChunk.java	83.33%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #15475      +/-   ##
============================================
+ Coverage     71.92%   71.93%   +0.01%     
- Complexity    63328    63370      +42     
============================================
  Files          5227     5227              
  Lines        296497   296492       -5     
  Branches      42830    42830              
============================================
+ Hits         213248   213279      +31     
+ Misses        65764    65744      -20     
+ Partials      17485    17469      -16     

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[reta]

@andrross may I ask please to reapprove? thank you!