WindowContainerTransaction: add KeyguardState.

This adds a HOP.KeyguardState class that keyguard related transitions
can pass to wct to communicate to core. Currently, it does nothing (all
the variables are default values), and Core does not really handle it
(it just no-ops), and is only set on the most simple case (Simple unlock
via swipe up).

Subsequent changes will address the TODOs.

Bug: 364930619
Test: Manually swipe up to make sure nothing breaks
Flag: EXEMPT no-op at the moment

Change-Id: I5e5890d8e82a1a3d1d9b930071fbd968f2c437bb