Register the single fingerprint sensor only if

there is no existing one. And do not register HIDL fingerprint hardware
sensor(s) if the VHAL is enabled.

Bug: 287456517
Test: adb shell dumpsys fingerprint on bramble (B5) device running
        with userdebug/eng build, and verify virtual fingerprint HAL
	does not present.
      atest BiometricsE2eTests:BiometricPromptAuthSuccessTest
Change-Id: I868f975446ec4b4b473c4fbc48370fbb68c0570c