[Accessibility] Added Mode attached property to easily group or exclude views from VoiceOver/TalkBack.

[Vetle444]

Summary

This PR introduces a new Accessibility.Mode attached property to improve VoiceOver/TalkBack accessibility support, along with comprehensive sample pages in the Components app demonstrating its usage.

What's Changed

New Accessibility Features

• Added Accessibility.Mode attached property with two modes:

  • GroupChildren - Combines all child elements into a single accessibility element, allowing screen readers to read all content in one focus gesture
  • ExcludeChildren - Excludes child elements from the accessibility tree, useful for decorative elements

• Implemented GroupEffect - Automatically collects text from all descendant elements and creates a combined semantic description for grouped containers

• Implemented ExcludeChildrenEffect - Excludes specified child views from the accessibility tree

Sample Pages

• Created VoiceOver samples structure in the Components app:

  • VoiceOverSamples.xaml - Overview page with navigation to specific examples
  • GroupChildrenSamples.xaml - Demonstrates GroupChildren mode with patient card, product card, and address card examples
  • ExcludeChildrenSamples.xaml - Shows how to exclude decorative elements and use custom semantic descriptions

• Added comprehensive localization (Norwegian & English) for all sample content

App Improvements

• Updated Components app to use TabBar instead of list view, with separate tabs for:
  • Resources
  • Components
  • Accessibility (new)