Show Choose/ConfirmLock before showing BiometricEnrollIntroduction

Skip button is now shown when ChooseLock is launched by
BiometricEnroll, otherwise users are forced to use passwords
(maybe good thing?)

Bug: 111548033

Test: Pin/pattern/pass must be set/confirmed before enrollment
Test: Able to enroll FP in SUW and Settings

Change-Id: Ic4bbeb539e4bf01c1c402dec308943292b43406d

src/com/android/settings/biometrics/BiometricsEnrollEnrolling.java

@@ -48,13 +48,6 @@ public abstract class BiometricsEnrollEnrolling extends BiometricEnrollBase
      */
     protected abstract boolean shouldStartAutomatically();
 
-    /**
-     * @return true if enrollment should finish when onStop is called.
-     */
-    protected boolean shouldFinishOnStop() {
-        return true;
-    }
-
     @Override
     protected void onStart() {
         super.onStart();
@@ -70,7 +63,7 @@ public abstract class BiometricsEnrollEnrolling extends BiometricEnrollBase
             mSidecar.setListener(null);
         }
 
-        if (shouldFinishOnStop() && !isChangingConfigurations()) {
+        if (!isChangingConfigurations()) {
             if (mSidecar != null) {
                 mSidecar.cancelEnrollment();
                 getSupportFragmentManager()