Add keyguardStateToCamera transition

The camera occluding activity can be launched
by double pressing the power button. When this happens, the first
power button press may immediately start a keyguard transition [1].
Then, the second power button press will launch the camera (an
occluding activity).

The desired behavior is to transition from the original state (before
any power button presses), rather than the started keyguard transition
from the first power button press [1]. Therefore, we use the 'from'
keyguardState of the last *finished* keyguard state rather than
the current running 'to' keyguard state.

Test: atest KeyguardTransitionInteractorTest
Fixes: 292506244
Change-Id: I50688200bb58515aa437747b9229e794f3d3a93c