Restrict unsupported API usage to Scene#mEnterAction/mExitAction/setCurrentScene

They were used via reflection in older versions of support transitions.
Starting from 26.0.0 it is not in use and there is no need to allow this usages.
Developers should update to the newer version of support libraries/androidx

Bug: 117521462
Bug: 117521646
Test: none
Change-Id: Ia1d5516a58c0deec68091d719065621fc588591b