bug fix: no transparency in collision scenes on rviz

[samialperen]

Description

On ROS humble and rviz2, I realized that collision scenes are not transparent even if their alpha value is not 1.0
This MR fixes this bug.

The fix already got merged before, but never got backported to humble. here is the link for the previous MR.

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

[sjahr]

Thanks!