Prevent case of unreleased TaskView surface

When the ControlsActiviyt showing a TaskView is opened over the
lockscreen and subsequently opened from the QS tile, the TaskView ends
up in an inconsistent state, overlaying over launcher and impossible to
dismiss without resetting.

This CL prevents opening the ControlsActivity from the tile if it's
already showing, instead just closing the shade. If there's a different
device controls activity showing, we know that there's no TaskView
currently displaying so we can launch the activity.

This does not address the underlying cause (we need Activity Embedding
for that), but prevents entering into the bad state, serving as
mitigation until we can replace the TaskView.

Test: manual, reproduce steps in bug.
Test: atest DeviceControlsTileTest
Fixes: 351895427
Flag: EXEMPT BUG_FIX
Change-Id: I5c42d98c9182aa4394ac76594ded1e11ee29fae9