[CS] Create NotifExpansionRepo to track expansion animation.

To remove @CentralSurfacesScope, we need to remove some dependency
cycles. Some of the cycles come from
NotificationLaunchAnimatorController directly depending on
NotificationShadeWindowViewController. This CL adds a new
NotificationExpansionRepo that the two classes can each depend on,
instead of depending on each other.

Bug: 277762009
Test: verified notif expansion animation still plays correctly
Test: verified via logging that the notif shade classes still get the
expansion animation boolean correctly set
Test: atest NotificationExpansionRepositoryTest
NotificationShadeWindowViewControllerTest
NotificationLaunchAnimatorControllerTest

Change-Id: If4292721dd629731c1153bf1ea6b2697983d4924