Fix LockIcon animation

There were occasions where the lock icon would not appear or at least
appear too late for the tests in b/309823964. The animation is not
necessary anymore because the underlying bug was fixed in the meantime.

Bug: b/309823964
Test: None
Flag: ACONFIG com.android.systemui.Flags.FLAG_NEW_AOD_TRANSITION TEAMFOOD
Change-Id: Ib4b6a9c3f2165f3b4eae4ecc77aac29ec4553f2b