StrongAuthTracker: Don't rely on USER_PRESENT

USER_PRESENT is sent via the background queue. A delay
there can cause us not to recognize that the user has
unlocked and prompt for the credential again, when trust
or fingerprint would be sufficient.

Also removes an obsolete reference to USER_PRESENT from
TrustManagerService.

Change-Id: Ie8d1a180170df5f0c8f9e71660504fd71eeacd99
Fixes: 27830458