Settings: Show single-touch wakeup setting on rear & front fps devices

Not sure why Google assumed that showing this setting is only useful
for devices with FP sensor built into a side-mounted power button.

Change logic to preserve check for side mounted (really, power-button
mounted) FP sensors, but allow any device which has a a rear or front
mounted sensor to show the relevant setting; so users can toggle it.

Bug: Enchilada (Oneplus 6, capacitive FP sensor on the back) no longer
wakes & unlocks from screen-off with FP sensor touch after QPR3 merge.

Test: Apply commit. "Touch to unlock anytime" setting is now visible;
enabling once again allows one-touch wakeup-and-unlock-on-successful-
FP-auth, does nothing with failed FP auth, while disabling toggle
requires pressing power button to wake screen first before FP auth
will unlock.

Change-Id: I4d8204b5fed7d43baa93d6793e7280260ae404d6