Added key names to Sizer controls to make it possible to override the styles

[0x5bfa]

Fixes

Added key names to the Sizer controls so you override the styles of the Sizer controls.

PR Type

• Other... Please describe: As the title describes

What is the current behavior?

You cannot override unless you copy and paste the style of SizerBase. The three deriviative controls even didn't have their own styles. And you couldn't create a style for one of them because all of them didn't set DefaultKeyStyle property.

What is the new behavior?

Being able to override.

PR Checklist

• Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• Based off latest main branch of toolkit
• Tested code with current supported SDKs
• New component
  • Documentation has been added
  • Sample in sample app has been added
  • Analyzers are passing for documentation and samples
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (if applicable)
• Header has been added to all new source files
• Contains NO breaking changes

Other information

I've tested this change in the sample app & with the Sizer tests on my local.

[michael-hawker]

Thanks @0x5bfa, we're usually pretty good about this pattern for Toolkit controls, but this is a bit odder case with the inheritance from a common style. Appreciate you taking a look into it! 🦙❤️

@Arlodotexe I did a quick pass, I think it all looks good. Mind doing a functional test of the changes? I think we have some basic loading tests for these, but we don't do much with the visuals.

[michael-hawker]

Held up by #758

[michael-hawker]

UWP branch had failed, not sure why...