Use custom drawable for Recents Go thumbnails (2/2)

Hook up the thumbnail drawable created in the first CL to the task
thumbnail so that the drawable automatically rotates and resizes based
off the device orientation.

Bug: 114136250
Bug: 131095241
Test: Go to app in landscape, go to recents, rotate => thumbnail rotates
Change-Id: Ib58e45ab3e94aeb080e47b1d5b38c221acce5ef3