[Backport 2.x] Improve the rejection logic for soft mode query groups during node duress (#16417)

[kaushalmahi12]

Backport 2.x for #16417

[github-actions]

✅ Gradle check result for a8fac13: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 71.77%. Comparing base (5617340) to head (a8fac13).
Report is 10 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...ain/java/org/opensearch/wlm/QueryGroupService.java	33.33%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x   #16438      +/-   ##
============================================
+ Coverage     71.75%   71.77%   +0.01%     
- Complexity    65231    65340     +109     
============================================
  Files          5312     5312              
  Lines        304646   304914     +268     
  Branches      44324    44425     +101     
============================================
+ Hits         218604   218851     +247     
- Misses        67796    67824      +28     
+ Partials      18246    18239       -7     

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