Remove transport-reactor-netty4/ plugin since it is not supported by 1.x line

[reta]

Description

Remove transport-reactor-netty4/ plugin since it is not supported by 1.x line

Related Issues

N/A

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)
• Public documentation issue/PR created

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[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/34218/
• CommitID: 9b2baab

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.59%. Comparing base (c681c78) to head (9b2baab).

Additional details and impacted files

@@             Coverage Diff              @@
##                1.x   #12481      +/-   ##
============================================
+ Coverage     77.56%   77.59%   +0.03%     
- Complexity    58736    58780      +44     
============================================
  Files          4223     4223              
  Lines        253560   253560              
  Branches      38701    38701              
============================================
+ Hits         196677   196761      +84     
+ Misses        40835    40828       -7     
+ Partials      16048    15971      -77     

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