Add Support for IValueConverter in Typed Bindings Extensions

[brminnick]

Description of Change

This PR adds support for IValueConverter with Typed Bindings extensions

Linked Issues

• Fixes [Proposal] Further enhance Bind typed binding support to provide IValueConverter support #179

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: Update to IValueConverter support for typed bindings MicrosoftDocs/CommunityToolkit#226

Additional information

Allows the use of IValueConverter with the new Typed Bindings extensions, such as CommunityToolkit.Maui.Converters.ColorToHexRgbStringConverter in the .NET MAUI Community Toolkit:

new Label().Bind<Label, ViewModel, Color, string>(Label.TextProperty,
				static (ViewModel viewModel) => viewModel.TextColor,
				converter: new ColorToHexRgbStringConverter());

[brminnick]

@bijington Are you able to update the docs for this PR?

I know you've already got a list of the binding examples that couldn't be updated when we implemented #155.

[bijington]

Great work @brminnick. There is just the minor comment around the unit test code but we probably don't need to change that

[brminnick]

Thanks Shaun! I agree that we could reuse the code in the Unit Test, but to be honest I've found it a bit of an anti-pattern to try and share code between Unit Tests. I copy/pasted Xamarin.CommunityToolkit.Markup.UnitTests and I wish I hadn't because it has so many base classes and helper methods that it became tough to maintain and tough to write new Unit Tests.

Thanks for helping with the Docs! I'll wait to merge this PR until we have a Docs PR queued up.

[bijington]

@bijington Are you able to update the docs for this PR?

I know you've already got a list of the binding examples that couldn't be updated when we implemented #155.

Here you go: MicrosoftDocs/CommunityToolkit#226