simplify UserAttributes#findUnresolvedAttributes

[rursprung]

Description

no functional change, this just simplifies the code. this is a follow-up to PR #5975

CC @ThyTran1402

Issues Resolved

n/a

Testing

unit test

Check List

• New functionality includes testing
• New functionality has been documented
• New Roles/Permissions have a corresponding security dashboards plugin PR
• API changes companion pull request created
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[rursprung]

the CI failure seems to be a false reject:

• What went wrong:
  A problem occurred configuring root project 'opensearch-security'.

java.io.IOException: Failed to load eclipse jdt formatter: java.lang.RuntimeException: java.net.SocketTimeoutException: Connect timed out

[nibix]

the CI failure seems to be a false reject:

re-running the jobs

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.79%. Comparing base (ea6087c) to head (bc44bcd).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6122   +/-   ##
=======================================
  Coverage   74.78%   74.79%           
=======================================
  Files         447      447           
  Lines       28467    28465    -2     
  Branches     4328     4329    +1     
=======================================
  Hits        21289    21289           
+ Misses       5184     5183    -1     
+ Partials     1994     1993    -1     

Files with missing lines	Coverage Δ
...opensearch/security/privileges/UserAttributes.java	82.14% <100.00%> (-2.24%)	⬇️

... and 12 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[rursprung]

not sure why code coverage went down - i deleted code, so the coverage should go up if it stupidly counts lines (if it counts invocations it should be the same). either way, i think the CI failure is a false-positive

[cwperks]

not sure why code coverage went down - i deleted code, so the coverage should go up if it stupidly counts lines (if it counts invocations it should be the same). either way, i think the CI failure is a false-positive

There's some randomization in the testing so -0.02% coverage can come up for a small change like this. Its not a blocking check, but helps give a maintainer insight into patch coverage for a PR.