Updated overview exit animation for 3 button navigation

Changed overview exit animation so that tiles don't slide off and only fade/scale in place for 3 button navigation. Previously, tiles would slide off when exiting for both gesture navigation and 3 button navigation. Now 3 button navigation exits with tiles staying in place.

Test: Manual
Fix: 245745939
Change-Id: I4144ed7e3ff29419df7fb13b6417ccc0a1f9dd45