AlertWindowNotification: Correctly load app label

Passes User ID to AlertWindowNotification to make sure that we can
correctly load app label for the ones installed in work profile.

Test: Install an app that can display over other apps in the work
profile, watch the notification title and content when it's drawing over
other apps. It should now display app label, rather than its package
name.

Change-Id: I872c0c0f6870a09c4ef1c372d7a87dec156f91fc