UDFPS Enrollment Refactor (5/N)

Adding minor touch ups, such as starting the
FingerprintEnrollConfirmation when enrollment has been completed.

Bug: 297082837
Test: atest
Change-Id: I7b3edebb141bdb3e4648f71527d45dc5a0185b60

tests/robotests/src/com/android/settings/biometrics/fingerprint2/fragment/FingerprintEnrollIntroFragmentTest.kt

@@ -90,7 +90,7 @@ class FingerprintEnrollIntroFragmentTest {
 
   private val navigationViewModel =
     FingerprintNavigationViewModel(
-      Introduction,
+      Introduction(),
       false,
       flowViewModel,
       interactor