Setup rendering environment before cmake runs

[azeey]

🦟 Bug fix

Summary

CMake checks if rendering is available to enable some tests, so the rendering environment needs to be set before CMake runs.

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 69.42%. Comparing base (1a61269) to head (2bd262e).
Report is 36 commits behind head on ign-gazebo3.

❗ Current head 2bd262e differs from pull request most recent head 6238454. Consider uploading reports for the commit 6238454 to get more accurate results

Additional details and impacted files

@@               Coverage Diff               @@
##           ign-gazebo3    #1965      +/-   ##
===============================================
- Coverage        77.98%   69.42%   -8.57%     
===============================================
  Files              255      266      +11     
  Lines            15041    18411    +3370     
===============================================
+ Hits             11730    12781    +1051     
- Misses            3311     5630    +2319     

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