Request notification permission (shows the system dialog if the user has not yet decided).
It is safe to call this on every launch — the dialog only appears once; subsequent calls
resolve immediately with the previously granted or denied state.
Returns Promise<boolean>
A Promise that resolves to true if granted, false if denied
Request notification permission (shows the system dialog if the user has not yet decided). It is safe to call this on every launch — the dialog only appears once; subsequent calls resolve immediately with the previously granted or denied state.