Add animations to Manage Windows menu.

Adds animations for opening/closing Manage Windows menu. Also changes
the pivot of the menu on the app header side to be the top left corner
to fit the spec.

Bug: 337915660
Test: Manual
Flag: com.android.window.flags.enable_desktop_windowing_multi_instance_features
Change-Id: I9f47ee95bbeacdd0bf9bc45f336fdee2614045f0