gd: Hide UI while game window undergoes resize animation.

This CL updates the Game Dashboard UI logic to hide all Game
Dashboard widget UI whenever the Game Window undergoes a resizing
animation caused by user input. This CL does not extend to the float
and maximize actions on the Game Window as these actions are not
classed as animation events.

      --gtest_filter=GameDashboardContextTest.GameDashboardSnapVisibility*

Bug: b:286922264
Demo: http://b/286922264#comment2
Test: ./out/Default/ash_unittests \
Test: Verified on emulator.
Change-Id: I5c27916ec846a6334395be5161fbbc74cdece1c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5519709
Reviewed-by: Prameet Shah <phshah@chromium.org>
Reviewed-by: Gina Domergue <gdomergue@google.com>
Commit-Queue: Khaya Kingston <khayak@google.com>
Cr-Commit-Position: refs/heads/main@{#1325196}