Add a delay between the photo picker and the crop UI.

This adds a short delay before showing the crop UI after the photo
picker, to allow the photo picker exit animation to complete.

An interaction between the picker exit animation and the crop entry
animation causes visual jank without this delay.

Bug: 224477967
Test: install and exercise UI
Change-Id: Iaae0703617c1a6eb2f0337e7642059d1788be058