Avoid going to SHADE_LOCKED when already in SHADE

It's not possible for the device to go to SHADE_LOCKED after you're
already unlocked, still it's possible that it would happen.

Added an extra condition to avoid it, and logs to catch the regression
if it happens again.

Fixes: 139259891
Test: pull down notification while authenticating
Change-Id: I5c2b81906fa444dfd07d040b81a527245d4130e6