Improve app name handling

Substitute app name requires a permission, which wasn't being checked in
NotificationManagerService. Now it will be stripped out if the app isn't
allowed to use it.
In addition now MediaDataManager simply checks that extra when getting the
app name, instead of recovering the builder to get it.

Bug: 242044723
Test: atest NotificationManagerServiceTest MediaDataManagerTest
Test: manual
Change-Id: I2529f1a76a2bd9036899d5341f8dd47677690d1d