Add more analyzers, enable unit tests for partial properties

[Sergio0694]

This PR introduces the following changes:

• Add more analyzers for partial properties
• Add more analyzer tests
• Copy all [ObservableProperty] field tests and enable them for partial properties too

Note

One of the new tests is blocked by dotnet/roslyn#76166.

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
• PR doesn't include merge commits (always rebase on top of our main, if needed)
• Tested code with current supported SDKs
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes
• Every new API (including internal ones) has full XML docs
• Code follows all style conventions