title: Onesignal promptPermission() is not applicable in Android
body: <p>i'm using <a href="https://pub.dev/packages/onesignal_flutter" rel="nofollow noreferrer">onesignal_flutter</a> to push notifications to my app, but im facing this error, i did everything in the docs, still facing the same problem, any solution ?</p>
  
  <p><a href="https://i.stack.imgur.com/WGibQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WGibQ.png" alt="enter image description here"></a></p>