AuthenticationCallback should not be cleared onAuthenticationFailed

Fixes: 38197608

Test: 1) enroll a finger
2) enter keyguard, touch sensor with an unenrolled finger
3) touch sensor with enrolled finger
4) phone should enter keyguard
5) do this test from screen off as well

Change-Id: I1c7b060888128b4a6b492fd6a7a8ebc85d2b3353