Note the following cases. This commit is catering for case 3:
1. User is listening for onNotificationDisplayed and is manually calling
the completionHandler
- manually called completionHandler is removed
- automatically called completionHandler is guarded against on iOS
native side
2. User is listening for onNotificationDisplayed and is not calling the
completionHandler:
- automatically called completionHandler is removed
3. User is not listening for onNotificationDisplayed
- On rn side we can only automatically call completionHandler if the
user _is_ listening. This means we need to detect if the user is
listening or not.