Update co-ex face failure message

Suggest to the user to use their fp sensor.

Test: atest KeyguardIndicationControllerTest
Test: enroll fingerprint and a different face. Then attempt
to authenticate with face, and receive a failure (matcher must run and not
recognize face). Observe two messages: "Can't recongize face" and
then, "Use fingerprint instead"
Fixes: 231382377

Change-Id: Ie969e0b1403a530ac589a8a121581656977c82a7