Don't do any animations for unstyled translucent activities

This is actually undefined (translucent activities should be
using Theme.Translucent); however, some apps have been assuming
the previous behavior (that it means no-animation). This CL
restores the previous behavior.

Bug: 267843636
Test: Open Photos, go to a photo, click "Edit".
Change-Id: I7073f4acfa1b5d4d72381130c9101e18282f5010