Add animations to Manage Windows menu in Taskbar

This change switches to using animations to open and close the Manage
Windows view is the multi instance menu of Taskbar. Previously the view
would just appear and disappear, but this makes it smoother.

Fix: 380921297
Bug: 315989246
Test: Open and close the Manage Windows view and observe the motion
Flag: com.android.launcher3.enable_multi_instance_menu_taskbar
Change-Id: I9fb85d4a3ee437bed53991aac7a240d536478f4b