ECM notification is not displayed when the user is NOT the primary one

EmergencyCallbackModeService only runs under the primary user
and its notification is only sent to the primary user.

Now use NotificationManager.notifyAsUser with UserHandle.All
to display this important notification to all users.

Test: Manual test
Fix: 144979126
Change-Id: I20247d83646d0f7952951c15e1a6b4c3a6fee3db
1 file changed