Remove "Allow persistent changes to the vendor overlay theme"

This reverts commit 2dc804be11444565e3d1d151c2a693db3ade94c0.
It also removes the related calls from UiModeManager.

Fixes: 32721178
Test: make & flash
Change-Id: Id371bccec611155cc6910e46b3277c3d27fc1c79
6 files changed