[A11y][VoiceOver] Set accessibility value for the sheet expansion state

[nodes11]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

Currently, the resizing handle of the bottom sheet does not read its current state (i.e. "Collapsed" or "Expanded"). This change adds that functionality to align with Apple system sheets and improve the VoiceOver experience.

I updateResizingHandleViewAccessibility to set the accessibilityValue on the resizingHandle based on the provided expansion state. Updated where updateResizingHandleViewAccessibility is called to ensure that the accessibility values are updated before the voiceover reads the new state.

Binary change

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

Verification

On iPhone, in the Fluent Test app, I validated that the "Expanded" value is read when the sheet is in an expanded state and that the "Collapsed" value is read when the sheet is in a collapsed state.

After:

RPReplay_Final1730406726.MP4

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

[joannaquu]

can you just call updateResizingHandleViewAccessibility in move(...)? or is the issue still that the value is wrong