Permanent notification permission denial

Ideally, we should guide users how to access Alerts again when they have permanently denied permission

- We may redirect users to app settings to grant permission
- Or just show the steps in rationale (user navigate themselves to app settings)

https://developer.android.com/training/permissions/requesting#handle-denial

Start by reading the linked Android permission guidance and locating the notification permission rationale and permanent-denial flow in the app. The work is done when users who permanently denied permission are either directed to app settings or shown clear steps to enable Alerts there.

Written by the indexing model from the issue text.