Fix condition to check if FRP is active in LockSettingsService

When the frp_enforcement flag is enabled, FRP will stay active
outside of Setup Wizard too, so checking if setup is complete is not
needed here.

Ignore-AOSP-First: Depends on internal changes that can't go into AOSP yet.
Bug: 341652439
Flag: EXEMPT bugfix
Test: atest & manual testing
Change-Id: I23a231cd64fee87334cc5ca521add55a6c954761