Fix issue with translucent animations

If a translucent has overridden their activityOpenEnter/exit
animation in the resources, they won't be used anymore because the
system always forces the translucent animations, which is a bug.

Instead, we only use the translucent animation in case the app has
not overridden their animations manually.

Test: Open WhatsApp profile picture.
Test: go/wm-smoke
Change-Id: I7e81815e78453392773ac2ac96c47540e6146381
Fixes: 78270476