React Native Example: prompt user to enable voice isolation

[twitchard]

Changes

• When starting a chat, the example now prompts the user to enable Voice Isolation mode on their mic, if it isn't already enabled. This involved adding wrappers to the AudioModule around the iOS native APIs for getting this information and navigating to where the user can set them.
• Various other cleanups/improvements that seemed appropriate to do while I was testing this and debugging my environment:
  • We upgrade to the latest Expo / React Native.
  • We remove the react-native-modal dependency because React Native provides a modal built-in.
  • Fix a type error { error: string } should be { message: string } (the implementation was correct but the type was wrong).
  • Removed a bunch of unnecessary try/catch -- I looked at the swift module and if there is no indication that the swift code can throw then there is no reason to .catch around the promise it yields.
  • Set a ref .current to null for a websocket connection to avoid a double disconnect.