[MSFNotification] Enable support for bottomPresentationPadding token

[nodes11]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

This change enables the MSFNotification to respect and respond to changes of the bottomPresentationPadding token. Previously, the control did not respect this token.

Changes:

• Register the tokenSet for updates. Call updateBottomPresentationPadding when an update occurs.
• Implement updateBottomPresentationPadding which updates the constant on the bottom constraint
• Change the constraintWhenHidden and constraintWhenShown properties from NSLayoutConstraint! to NSLayoutConstraint? and make needed updates to support this change. We should avoid using implicitly unwrapped properties at all costs.

Binary change

(how is our binary size impacted -- see https://github.com/microsoft/fluentui-apple/wiki/Size-Comparison)

Verification

• Validated in the demo application and the change behaves as expected.
• Validated that the change fixes the internal usecase.

Visual Verification

Before	After
Screenshot or description before this change	Screenshot or description with this change

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