Polish app => recents animation (3/N)

This CL takes the current scale down animation and updates its
interpolators and durations to match the UX spec. In addition, we move
the core logic to a helper method as the whole remote animation will
have other animations as well in the future.

Bug: 132112131
Test: Manual
Change-Id: I68b1d623b1b2c980dc34e41bbb5460cc021b5887