Narrator announces changes to accessibilityState

[agniuks]

Description

This PR adds UIA events when accessibilityState has changed which will ensure that accessibility clients like Narrator can announce these types of changes to the user.

Type of Change

• Bug fix (non-breaking change which fixes an issue)

Why

Resolves: #8491

What

Added peer.RaisePropertyChangedEvent() calls when selected, disabled, checked, or expanded state has changed.

Screenshots

Here's an example that togggles Expand/Collapse state, highlighted portion is what Narrator announces when the touchable is clicked.

<TouchableHighlight
          style={styles.item}
          accessibilityLabel="Group Expand Collapse Button"
          accessible={true}
          accessibilityRole="none"
          accessibilityState={{expanded: this.state.displayText}}
          onPress={() => {
            this.setState({displayText: !this.state.displayText});
          }}>
     <Text style={styles.text}>Group Expand/Collapse</Text>
</TouchableHighlight>

Testing

Tested through Narrator that changes to each of the accessibility states (selected, disabled, checked, or expanded) are announced when the appropriate accessibilityRole is set.

Microsoft Reviewers: Open in CodeFlow

[chiaramooney]

👍