[flexiglass] Fixes issue where user management settings didn't show

In the issue, when the auth method is SWIPE and the device is not yet
entered, opening the user management activity from the icon in the
footer of the QS scene incorrectly stays on the gone scene and doesn't
start the activity.

The fix is to lean more heavily on the currentScene flow instead of the
transitionState flow that KTF is set up to use. This way, the timing of
the excuteDismissAction and resetDismissAction is correct (first,
exectute, then reset).

Fix: 366282915
Test: unit test added. It fails withoug the fix and succeeds with it
Test: manually verified the mentioned user flow with SWIPE and with
PATTERN to make sure it always works right
Flag: com.android.systemui.scene_container

Change-Id: I987d0dc88a35b4afeddc87c75e2dd71e853aee8c