Messaging supports removeListener API

[molvqingtai]

When using onMessage, need to support removing the listener but not all of it, especially when using react StrictMode.

useEffect(() => {
  onMessage('custom-event', () => {
    // do some thing...
  })

  return () => {
    // removeAllListeners()
    removeListener('custom-event'')
  }
})

[aklinker1]

onMessage returns a function that, when called, removes the listener.

useEffect(() => {
  const removeListener = onMessage('custom-event', () => {
    // do some thing...
  })

  return () => {
    removeListener('custom-event'')
  }
})