Remove view from existing clock plugin when new plugin connects.

Assuming that the most recently connected plugin is the active
clock face. This should be updated when it is possible for
the user to select a clock face.

Bug: 118440898
Test: Added tests to KeyguardClockSwitchTest.
Change-Id: I1c38005b4d7d32a27a8d41806390338ebcab458b
2 files changed