Fix app domain unloading issue on .NET Framework

[Sergio0694]

Port of CommunityToolkit/dotnet@e2b3361.

Didn't really see any other commits already in https://github.com/CommunityToolkit/dotnet that would meet the hotfix bar for 7.1.2, so I think it's just this one hotfix we need on top of the other stuff that's already here on main, eg. the animation fix.

Fixes

• Microsoft.Toolkit.Mvvm v7.1.1 will freeze NUnit tests dotnet#14
• MVVM Toolkit not correctly unloading using Appdomain.Unload() with Version 7.1 dotnet#12

PR Type

What kind of change does this PR introduce?

• Bugfix

What is the current behavior?

The app domain cannot be loaded on .NET Framework when using WeakReferenceMessenger.

What is the new behavior?

Auto trimming is disabled when running on .NET Framework, which solves the issue.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• New component
  • Pull Request has been submitted to the documentation repository instructions. Link:
  • Added description of major feature to project description for NuGet package (4000 total character limit, so don't push entire description over that)
  • If control, added to Visual Studio Design project
• Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• New major technical changes in the toolkit have or will be added to the Wiki e.g. build changes, source generators, testing infrastructure, sample creation changes, etc...
• 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

[ghost]

Thanks Sergio0694 for opening a Pull Request! The reviewers will test the PR and highlight if there is any conflict or changes required. If the PR is approved we will proceed to merge the pull request 🙌

[michael-hawker]

Shipped as part of 7.1.2, I don't see our milestone for that though.