Fix dark mode issues with new color system

[mischreiber]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

Fix broken dark mode on some UIKit screens.

There's some subtle misbehavior when creating a UIColor from a Color whose value is defined by a color resolver. It's likely an Apple bug, but to work around it in the meantime, this reverts back to the 0.30 and earlier behavior of storing raw color data as DynamicColor values.

Binary change

Coming soon!

Verification

Ensured light and dark modes all function as expected in both UIKit and SwiftUI.

Visual Verification

Before	After

Pull request checklist

This PR has considered:

• Light and Dark appearances
• iOS supported versions (all major versions greater than or equal current target deployment version)
• VoiceOver and Keyboard Accessibility
• Internationalization and Right to Left layouts
• Different resolutions (1x, 2x, 3x)
• Size classes and window sizes (iPhone vs iPad, notched devices, multitasking, different window sizes, etc)
• iPad Pointer interaction
• SwiftUI consumption (validation or new demo scenarios needed)
• Objective-C exposure (provide it only if needed)

Microsoft Reviewers: Open in CodeFlow