Fix bug in which some Views were not executing enter transition.

Bug 31236341

Strips the views from the enter transition as soon as they
are ready to prevent stripping from happening after
the shared element starts -- possibly changing the views
to strip. The stripped views are now excluded explicitly
from transitions when they are configured.

Test: Ia8c4e876d9978af17f1a34b0d35cf33e00389ab3

Change-Id: Id8f6132db173a9011f6346de70cfe770ddee1244