Make use of a specific ios version in the TFM

[bijington]

Description of Change

Linked Issues

• Fixes [BUG] Could not set up parent class, due to: Invalid generic instantiation #1075

PR Checklist

• Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

[brminnick]

Hey Shaun! Two quick thoughts:

1. If we make this change for iOS, let's also do it for MacCatalyst too
2. Is it possible to create unit test that validates this fixes the NativeAOT/Trimming bugs?
   • We may need to first merge the Device Tests PR
   • If you can figure out how to get CI / CD pipeline working for the Device Tests PR, we can merge it now to help you complete this bug fix
     • i.e. We don't need to write a complete DeviceTest suite in order to first merge the Device Tests PR

(Also - If this is PR still a work-in-progress, could you flip it to be a Draft PR please? I get distracted by shiny new PRs and want to review them, but I wait when the PR is still in Draft.)

[bijington]

Hey Shaun! Two quick thoughts:

1. If we make this change for iOS, let's also do it for MacCatalyst too

2. Is it possible to create unit test that validates this fixes the NativeAOT/Trimming bugs?

   • We may need to first merge the Device Tests PR

   • If you can figure out how to get CI / CD pipeline working for the Device Tests PR, we can merge it now to help you complete this bug fix

     • i.e. We don't need to write a complete DeviceTest suite in order to first merge the Device Tests PR

(Also - If this is PR still a work-in-progress, could you flip it to be a Draft PR please? I get distracted by shiny new PRs and want to review them, but I wait when the PR is still in Draft.)

This isn't aimed at fixing any NativeAOT or Trimming bugs but aimed at the TypeLoadException due to mismatched TFMs when developers consume our library. Based on this issue/discussion xamarin/xamarin-macios#21335
I mostly just wanted to see if it would build for now which it does not.

I'll be happy to work on any possible testing options although I am not sure how we can right now.

[bijington]

I am actually starting to wonder whether this might also fix other issues such as #1374 based on this documentation page https://learn.microsoft.com/en-us/dotnet/standard/frameworks#precedence I read it as apps could be built targeting net8.0 support as this may be closer to what the developer is targeting. It's either going to help or make it worse...