Update Unit Tests to be more Cross Platform Friendly

[dansiegel]

Summary

Currently the Unit Tests for Forms provides a degree of abstraction for unit tests that allow us to write tests once for both DryIoc and Unity Container. We need to expand this so that many of the tests that we have for Wpf particularly on Regions and also Dialogs which now share the same abstraction layer from core will have the ability to run across Maui, Wpf, & Uno Platform. This will provide us with better overall test coverage and provide some assurance that the APIs are being correctly tested across all platforms.