Remove enterprise disclosure from lock screen

There's duplication and the persistent field is already on quick
settings, it's also taking up space and confusing users, since
it's too close to where we put error messages.

Fixes: 140939386
Fixes: 139966195
Fixes: 140053632
Test: visual
Change-Id: I06100e0e44db03e4998885ecfa0ffa301d1f5c65