Disable flaky VisualAt test on mac

[iche033]

Signed-off-by: Ian Chen [email protected]

🦟 Bug fix

Summary

Disable Scene.VisualAt test as it's flaky on macOS, see #758 (comment)

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

Merging #767 (222843a) into gz-rendering7 (59dc8e4) will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           gz-rendering7     #767   +/-   ##
==============================================
  Coverage          75.48%   75.48%           
==============================================
  Files                164      164           
  Lines              14363    14363           
==============================================
  Hits               10842    10842           
  Misses              3521     3521           

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