Enable Mesa workaround also on Mesa 21

[peci1]

Description

This enables the Mesa workaround for Mesa 21.x, too (and all future Mesa 2?.x versions).

My system reports:

GL_RENDERER   = AMD RENOIR (DRM 3.40.0, 5.10.24-051024-generic, LLVM 11.0.1)
GL_VERSION    = 4.6 (Compatibility Profile) Mesa 21.0.0 - kisak-mesa PPA
GL_VENDOR     = AMD

The fix merged in #1588 is limited to Mesa 20.x only, but the problems it works around are present in 21.x, too.

Checklist

• If you are addressing rendering issues, please provide:
  • Images of both, broken and fixed renderings.
  • Source code to reproduce the issue, e.g. a YAML or rosbag file with a MarkerArray msg.
• If you are changing GUI, please include screenshots showing how things looked before and after.
• Choose the proper target branch: latest release branch, for non-ABI-breaking changes, future release branch otherwise.
  Due to the lack of active maintainers, we cannot provide support for older release branches anymore.
• Did you change how RViz works? Added new functionality? Do not forget to update the tutorials and/or documentation on the ROS wiki
• While waiting for someone to review your request, please consider reviewing another open pull request to support the maintainers of RViz. Refer to the RViz Wiki for reviewing guidelines.

[rhaschke]

Thanks.