Switch: Improve Accessibility

Summary: On Android, `Switch` does not currently read its role as a "button". This fixes that and makes it consistent with iOS.

Reviewed By: sahrens

Differential Revision: D13136253

fbshipit-source-id: 0de5d54772d204168138cb2af7815cc458f72682

Libraries/Components/Switch/Switch.js

@@ -164,6 +164,7 @@ class Switch extends React.Component<Props> {
       <SwitchNativeComponent
         {...props}
         {...platformProps}
+        accessibilityRole={props.accessibilityRole ?? 'button'}
         onChange={this._handleChange}
         onResponderTerminationRequest={returnsFalse}
         onStartShouldSetResponder={returnsTrue}