Use attached object colors as is in Rviz plugin

[ANogin]

Description

Fixes #3273. As explained in #3273, there is some weird code from 2013 that messes up the colors of attached objects in rviz, overriding the colors provided via the planning scene interface with potentially out of range values. This removes the erroneous code and just passes the colors as is.

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[rhaschke]

I'm curious under which circumstances this bug manifested itself. I never noticed a fully-white attached body.
Anyway, given that fact, that nobody noticed that issue yet, we can safely use the original color.

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 45.58%. Comparing base (524ca4f) to head (3365d14).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...gin_render_tools/src/robot_state_visualization.cpp	0.00%	2 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3274      +/-   ##
==========================================
- Coverage   45.98%   45.58%   -0.39%     
==========================================
  Files         716      716              
  Lines       62395    62372      -23     
  Branches     7544     7542       -2     
==========================================
- Hits        28683    28426     -257     
- Misses      33545    33780     +235     
+ Partials      167      166       -1     

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[rr-mark]

I'm curious under which circumstances this bug manifested itself. I never noticed a fully-white attached body. Anyway, given that fact, that nobody noticed that issue yet, we can safely use the original color.

I think we were previously seeing this problem, but had a workaround to avoid it (see e.g. https://robotics.stackexchange.com/questions/113543/how-can-attached-collision-objects-be-recoloured-in-rviz2).

It's relatively hard to change the colour of an attached collision object away from default, so I'm not surprised not many people ran into this behaviour.

[rhaschke]

Now, I'm even more surprised: as MoveIt1 used the same code, I'm wondering why it didn't display the attached object as white.

[rr-mark]

Now, I'm even more surprised: as MoveIt1 used the same code, I'm wondering why it didn't display the attached object as white.

The behaviour we saw before our workaround was that attached collision objects would be the default colour until recoloured, at which point they would be white for any valid colour input.

Our workaround is to have a separate node listening to moveit's planning scene, recolouring all the objects, and republishing to rviz. Hopefully that won't be needed after we start using this PR.