Recalculate max # notifs on keyguard w/ udfps

- By default, show the new lockscreen on devices that have UDFPS
- Hide lock icon if UDFPS is on the device (eventually isUdfpsEnrolled
should check enrollment)
- Don't take into account the lock icon when calculating the clock
position top padding in the KeyguardClockPositionAlgorithm

Bug: 165260390
Test: atest SystemUITests
Change-Id: Ia3c644256a8901144ebc6362df4d9585a6a29165