SystemUI: nuke broadcast tile from user tile list

Any app which is smart enough to mess with QS tiles has the ability to
make their own broadcast tile.

Ref: CYNGNOS-1814

Change-Id: I5553692b3ac4439c9c967a7209e6f687c7aef4f9
Signed-off-by: Roman Birg <roman@cyngn.com>