fix launcher crash when accessing Notification dots in home settings

Bug: 148815606
Test:
1.  Make sure launcher doesn't have notifications permission
    (Settings -> search for "notification access" -> Disable access for Launcher)
2.  Home settings -> Notification Dot
3.  Verify Alert Dialog pops up without crash

Change-Id: I399b6aad46e8a3e185199a2909adac9f75596b50