Fixes default setting for showing MultiUserSwitch

By default, UserManager enables UserSwitch if no decission has been made
before. However, in QS, we want the UserSwitcher not to show unless the
user has explicitly enabled UserSwitch

Fixes: 129898837
Test: manual, after Full wipe
Change-Id: Ib2a0c10dff910199ce5c60d9e578efee3899cbb9