Add icon scale and alpha animation for entering downloading state from pending state

When we enter downloading state from being in pending state, we want to run an animation that animates the process of scaling down the icon as well as removing the overlay with an animation

Bug: 254858049
Test: Download a couple of apps with ENABLE_DOWNLOAD_APP_UX_V2 flag on
Change-Id: Ie4f378874aa3cf6597c02b4d7043a34eb51d838c