Build in shade support into KeyguardTransitionAnimationFlow

ShadeDependentFlows was useful but inefficient, as every instance was
using `sample` on the same data. More importantly, there was no
guarantee of ordering with emission of the STARTED event, and it was
possible to capture the shade state after the animation had started.

Adds a new `sharedFlowWithShade` method that captures the shade/qs
state on animation start, and passes that value back to onStep,
onCancel, and onFinish so animations can make the right decision.

Test: atest KeyguardTransitionAnimationFlowTest
Bug: 392209635
Flag: EXEMPT performance fix
Change-Id: If4024b6691d0408557aae78f8e0bb7ce016ad4b0