Enable MSAA by default

[jjspace]

Description

As part of updating our visual quality settings we're enabling MSAA by default with 4 samples. This decently improves the way things look in the viewer and doesn't seem to have a significant impact on framerate. MSAA can still be disabled by setting scene.msaaSamples = 1.

I also removed the setting in any sandcastles that were previously setting msaaSamples = 4 as it's no longer needed.

Issue number and link

Part of #12126

Testing plan

• Create a new Viewer or CesiumWidget and check the value of msaaSamples, it should be 4;
  • local sandcastle to log the default value
• Options passed to constructors should still override the default
• Check that tests pass
• Do a pass on any existing sandcastles that are already on the heavier side and make sure the framerate is still ok.

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @jjspace!

✅ We can confirm we have a CLA on file for you.

[ggetz]

Awesome! My eyes thank you @jjspace.