Stop face auth requests when users are typing

We don't want the bouncer to be dismissed right under the user's finger
when typing.
Let's abort face auth after we start typing.

Test: solve challenge when face auth is running
Test: repeat for pin/pattern/password
Fixes: 136525169
Change-Id: I8f1ccbca4be9c84f5cb108618b84aefe03b74cc4