ForwardPort #2388 Fix unused gcc warnings

[Blast545]

🦟 Bug fix

Fixes gcc warnings appearing in CI:
https://build.osrfoundation.org/job/gz_sim-ci-main-jammy-amd64/66/gcc/

Summary

Forward port to fix warnings on main

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.94%. Comparing base (098085b) to head (6dfb9ed).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2395      +/-   ##
==========================================
- Coverage   65.95%   65.94%   -0.01%     
==========================================
  Files         327      327              
  Lines       31319    31318       -1     
==========================================
- Hits        20655    20654       -1     
  Misses      10664    10664              

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