[flexiglass] use LSToGoneTransitionViewModel for keyguardAlpha during LS -> GONE

With flexiglass on, using the shade/QS alpha for keyguard when on Gone scene was causing the stack to flicker when going from LS -> Gone scene, as well as during the first shade invocation after going from LS -> Gone. This CL switches us over to the alpha provided by LockscreenToGoneTransitionViewModel and only uses shade/QS alpha when shade/QS are actually occluding keyguard.

Bug: 364887368
Test: Manually verified keyguard alpha during LS -> Gone transition
Flag: com.android.systemui.scene_container
Change-Id: I837156b5e39cfc512ec7564824683a5acb6fc98b
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt
index f39af18..472e779 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt
@@ -475,19 +475,28 @@
     }
 
     fun keyguardAlpha(viewState: ViewStateAccessor, scope: CoroutineScope): Flow<Float> {
+        val isKeyguardOccluded =
+            keyguardTransitionInteractor.transitionValue(OCCLUDED).map { it == 1f }
+
+        val isKeyguardNotVisibleInState =
+            if (SceneContainerFlag.isEnabled) {
+                isKeyguardOccluded
+            } else {
+                anyOf(
+                    isKeyguardOccluded,
+                    keyguardTransitionInteractor
+                        .transitionValue(scene = Scenes.Gone, stateWithoutSceneContainer = GONE)
+                        .map { it == 1f },
+                )
+            }
+
         // Transitions are not (yet) authoritative for NSSL; they still rely on StatusBarState to
         // help determine when the device has fully moved to GONE or OCCLUDED state. Once SHADE
         // state has been set, let shade alpha take over
         val isKeyguardNotVisible =
-            combine(
-                anyOf(
-                    keyguardTransitionInteractor.transitionValue(OCCLUDED).map { it == 1f },
-                    keyguardTransitionInteractor
-                        .transitionValue(scene = Scenes.Gone, stateWithoutSceneContainer = GONE)
-                        .map { it == 1f },
-                ),
-                keyguardInteractor.statusBarState,
-            ) { isKeyguardNotVisibleInState, statusBarState ->
+            combine(isKeyguardNotVisibleInState, keyguardInteractor.statusBarState) {
+                isKeyguardNotVisibleInState,
+                statusBarState ->
                 isKeyguardNotVisibleInState && statusBarState == SHADE
             }