Fix pie controls being disabled by launcher gestures.

Some launchers have gestures for expanding/collapsing the status bar
from swipe gestures which call the respective StatusBarService methods
even if the status bar isn't visible due to expanded desktop. Because of
that, the status bar code internally thinks the expansion is carried out
(even if invisible), thus disabling the bottom pie controls in the
process.
Fix that by making PhoneStatusBar aware of it being hidden by expanded
desktop and ignoring the expand call in that case.

Change-Id: If386ca953517d9b5efcb6cb9054f5c5e6a9e0bc4