Add dozeTimeTick method to ClockPlugin interface.

dozeTimeTick implementations provided by clock plugins
should update the time of the clock while the device
is dozing and deal with burn-in related issues.

Bug: 119035943
Test: KeyguardClockSwitchTest passes locally.
Test: Custom clock updates with time on AOD screen.
Change-Id: I5c31e6d856c5a80dc3e501831dda5a62c0be5ba0