[MenuItem][MacOS] Fix "onClick" being called twice when invoking menu item via ENTER / SPACE

[lawrencewin]

Platforms Impacted

• iOS
• macOS
• win32 (Office)
• windows
• android

Description of changes

React Native MacOS pressables handle a special case for ENTER / SPACE keys for the keyDown / keyDown event handlers: these keys should also be interpreted as presses, thus causing the event to be passed to the onPress handler. The code for this is found here: https://github.com/microsoft/react-native-macos/blob/48e607706bfcc25b4c28eba1aa352f409c02975e/packages/react-native/Libraries/Pressability/Pressability.js#L580-L617

For the MenuItem, we pass onInvoke, the handler for clicks and keypresses, into both press and keyDown / keyUp handlers. The code snippet above, then causes onClick to be called twice on the platform. We can fix this by simply marking the event as handled, so onClick is only called once.

Verification

Tested locally, video:

menu.item.working.mp4

Pull request checklist

This PR has considered (when applicable):

• Automated Tests
• Documentation and examples
• Keyboard Accessibility
• Voiceover
• Internationalization and Right-to-left Layouts