[RESTRICT AUTOMERGE] Fix NullPointerException when mLockPatternUtils is not set.

Test: atest LockTaskControllerTest
Bug: 132593073
Change-Id: I1bfacd5992569d67cdaa526b18d1c426a366babb
(cherry picked from commit fa1b986746ad7d9ebab6a34a0bfafd0a93267d5b)
1 file changed