Change to launch FingerprintEnrollIntroductionInternal directly when no fingerprint enrolled and fingerprint is the only biometrics. This avoids the flicker of FingerPrintSettings before showing the enroll introduction.
This partially reverts the change in ag/19732076.
Bug: 256334588
Test: manual test following cases on fp-only devices, and enable don't
keep activity and test them again.
1. fp enrollment on SUW
2. fp add another on SUW
3. add first fp on Security Settings
4. add another fp on Security Settings
Test: atest FingerprintStatusUtilsTest BiometricsSafetySourceTest
Change-Id: I057b00fbca6660012887ebedf4d65c2c3d35792b
6bed01f315