[Backport 2.x] Replaced uses of SecurityRoles by Set<String> mappedRoles where the SecurityRoles functionality is not needed

[opensearch-trigger-bot]

Backport 681a944 from #4432.

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 65.37%. Comparing base (87e98f8) to head (df0cebf).

Additional details and impacted files

@@            Coverage Diff             @@
##              2.x    #4458      +/-   ##
==========================================
- Coverage   65.38%   65.37%   -0.01%     
==========================================
  Files         311      311              
  Lines       21868    21863       -5     
  Branches     3550     3548       -2     
==========================================
- Hits        14298    14294       -4     
+ Misses       5802     5800       -2     
- Partials     1768     1769       +1     

Files	Coverage Δ
...earch/security/privileges/PrivilegesEvaluator.java	72.17% <50.00%> (+0.05%)	⬆️
...rity/privileges/ProtectedIndexAccessEvaluator.java	74.46% <66.66%> (+0.99%)	⬆️

... and 2 files with indirect coverage changes