Plumb Scene-transition tag through shell transitions

This was being ignored, but we should plumb the information
through so that the defaulthandler doesn't apply an animation
on top of the scene-transition (which expects a jumpcut).

Bug: 190806800
Test: take screenshot, then pres edit button
Change-Id: Ib1bda6220012cf3b8f85fccac4cc50e1327b9886