[0.80-stable] Cherry-pick: Add UIA HeadingLevel behaviour for Fabric architecture

[Copilot]

This PR cherry-picks commit 8826a55 from main to the 0.80-stable branch.

Summary

This change adds UI Automation (UIA) HeadingLevel support for the Fabric architecture in React Native Windows. This enables proper accessibility behavior for heading elements, allowing screen readers and other assistive technologies to correctly identify and navigate heading levels (H1-H9) in Fabric-based applications.

Changes

Core Implementation

• Added GetHeadingLevel() function in UiaHelpers.cpp that maps accessibility levels (1-9) to UIA HeadingLevel constants when the element has a heading role
• Added GetControlTypeFromRole() and GetControlTypeFromString() helper functions to properly map React Native roles to UIA control types
• Updated CompositionDynamicAutomationProvider.cpp to query and expose the HeadingLevel property via IUIAutomationElement8

Test Updates

• Updated accessibility example to use role="heading" and accessibilityRole="header" to demonstrate the feature
• Updated test snapshots to reflect:
  • HeadingLevel property values (80051 for level 1, 80052 for level 2, etc.)
  • ControlType change from 50026 (group) to 50020 (text) for heading elements
  • LocalizedControlType change from "group" to "text" for heading elements

Conflict Resolution

One merge conflict was resolved in AccessibilityTest.test.ts.snap where the 0.80-stable branch includes "Name" fields in test snapshots that aren't present in main. The resolution preserved the "Name" fields while accepting the LocalizedControlType changes from the cherry-picked commit.

Testing

The changes include updated test snapshots that validate:

• HeadingLevel property is correctly exposed for elements with heading roles
• Accessibility levels 1-2 map to HeadingLevel1 and HeadingLevel2 respectively
• Control types are correctly mapped for heading elements

Fixes accessibility navigation and screen reader support for heading elements in Fabric architecture.

Original prompt

cherry pick this commit to 0.80-stable and raise PR

8826a55

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Microsoft Reviewers: Open in CodeFlow

[vineethkuttan]

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