[Backport 2.x] Abstract out RemoteFsTranslogWithPinnedTimestamps

[opensearch-trigger-bot]

Backport deeb2de from #15579.

[github-actions]

❌ Gradle check result for 6d74e2c: 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 6d74e2c: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 85.62874% with 24 lines in your changes missing coverage. Please review.

Project coverage is 71.63%. Comparing base (bd57e5d) to head (6d74e2c).
Report is 6 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...index/translog/RemoteFsTimestampAwareTranslog.java	84.61%	17 Missing and 5 partials ⚠️
...rg/opensearch/index/translog/RemoteFsTranslog.java	90.47%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x   #15623      +/-   ##
============================================
+ Coverage     71.55%   71.63%   +0.07%     
- Complexity    63951    63958       +7     
============================================
  Files          5243     5244       +1     
  Lines        299321   299354      +33     
  Branches      43568    43574       +6     
============================================
+ Hits         214193   214445     +252     
+ Misses        67177    66974     -203     
+ Partials      17951    17935      -16     

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