Hide heightmaps in segmentation camera

[iche033]

🦟 Bug fix

Alternative to #441

Summary

Disable heightmaps in segmentation camera until we can label it by setting its material

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• 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

[adlarkin]

LGTM if CI comes back green. Thanks!

[codecov]

Codecov Report

Merging #443 (700f37b) into main (eb7d6ea) will increase coverage by 0.00%.
The diff coverage is 50.00%.

❗ Current head 700f37b differs from pull request most recent head 063eccc. Consider uploading reports for the commit 063eccc to get more accurate results

@@           Coverage Diff           @@
##             main     #443   +/-   ##
=======================================
  Coverage   53.49%   53.49%           
=======================================
  Files         192      192           
  Lines       19554    19566   +12     
=======================================
+ Hits        10460    10467    +7     
- Misses       9094     9099    +5     

Impacted Files	Coverage Δ
ogre2/src/Ogre2Heightmap.cc	0.00% <ø> (ø)
ogre2/src/Ogre2SegmentationMaterialSwitcher.cc	61.22% <40.00%> (-1.55%)	⬇️
ogre2/src/Ogre2Scene.cc	74.34% <100.00%> (+0.08%)	⬆️
...e/ignition/rendering/base/BaseGaussianNoisePass.hh	100.00% <0.00%> (+3.33%)	⬆️

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