Add notification permission request on app start

Before this change the behavior would be to request permissions whenever
the notification channel is created. This may be a bit late for some of
the use cases so moving it to app start for simplicity.

This permission can be denied twice before it's considered "Dont ask
again"

Fixes: 210137606
Test: Manual for new app install permission ask on start
Change-Id: I61ba0891c6cb5a093d8d28453ed9b9d7fa40e3a2