[bc25] Add an animated transition for `NotificationsShadeScene`.

This is a basic transition for the shade from both `Gone` and
`Lockscreen` scenes. Once a motion spec is available, this transition
will be revised and improved.

Test: Manually tested by opening and closing the notifications shade on
a foldable device both in a folded and unfolded configuration.
Test: Unit tests build and pass.
Bug: 342463447
Flag: com.android.systemui.dual_shade

Change-Id: I47eb0e460250b5069c724b1453a5efdd8d28f9bb