Custom Lockscreen Shortcut preview reflects whether a shortcut is activated

Disable the activated state while in preview mode.

Bug: b/269617901
Test: manual; toggle on a shortcut, go to the picker, observe proper colors/UI
Test: KeyguardBottomAreaViewModelTest.kt updated to handle new behavior
Change-Id: I084ed4deae605a36c86304e921c9665d72ac0d50