Allow FP authentication while screensaver (not AOD) is on

FP authentication should be allowed whenever the screen saver is showing,
even if the device is not locked yet.

Fixes: 64537131

Test: 1) Disable AOD
2) Manually start screen saver from Settings
3) Before device is locked, touch FPS, device unlocks and wakes

Test: Do the same as the first test, but wait for the device to be locked
before touching FPS. Device unlocks and wakes

Test: Do the first two tests again with AOD enabled

Change-Id: Icd93a2e73d581e61b1c158b16de243722bd5680c