Adds property indicating presence of power button fingerprint sensor

Adds boolean field is_powerbutton_fps indicating whether device has a
power button fingerprint sensor, and adds is_powerbutton_fps to dump sys

Test: adb shell dumpsys fingerprint
Test: adb shell dumpsys biometric

Bug: 183642196
Change-Id: Ib433e6f54a57692be23291a55abba5cea8ed0d9d
Merged-in: Ib433e6f54a57692be23291a55abba5cea8ed0d9d