Fix BiometricPrompt layout for UDFPS in landscape

Makes some fixes to the logic for BiometricPrompt so that it better
supports UDFPS in landscape:
1. Fix measurement used for UDFPS icon placement in landscape
2. Move prompt to correct position when falling back to UDFPS
3. Properly save/restore state for the face -> fingerprint prompt

Test: atest com.android.systemui.biometrics
Test: Manually tested face and/or fingerprint auth w/ device rotation

Fixes: 190832486
Change-Id: Iac32e97f870998d9815817c348e23cfd9d020215