Fix issues with SUW on fingerprint devices

Fixes the following issues related to fingerprint/face in Setup Wizard:
- Ensures super.onStop() is called by all enrollment-related Activities

Test: Proceed through Setup Wizard on factory reset Pixel 3 XL
Before: Periodic crash dialogs and stuck on fingerprint enrollment
After: Able to proceed through wizard and enroll fingerprint normally

Bug: 147325159
Change-Id: I76eb8c944140aa68f78eaea3702f440102b779c6

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

@@ -60,6 +60,8 @@ public abstract class BiometricsEnrollEnrolling extends BiometricEnrollBase
 
     @Override
     protected void onStop() {
+        super.onStop();
+
         if (mSidecar != null) {
             mSidecar.setListener(null);
         }
@@ -77,6 +79,12 @@ public abstract class BiometricsEnrollEnrolling extends BiometricEnrollBase
         }
     }
 
+    @Override
+    protected boolean shouldFinishWhenBackgrounded() {
+        // Prevent super.onStop() from finishing, since we handle this in our onStop().
+        return false;
+    }
+
     @Override
     public void onBackPressed() {
         if (mSidecar != null) {

src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrolling.java

@@ -217,13 +217,15 @@ public class FingerprintEnrollEnrolling extends BiometricsEnrollEnrolling {
 
     private void stopIconAnimation() {
         mAnimationCancelled = true;
-        mIconAnimationDrawable.stop();
+        if (mIconAnimationDrawable != null) {
+            mIconAnimationDrawable.stop();
+        }
     }
 
     @Override
     protected void onStop() {
-        stopIconAnimation();
         super.onStop();
+        stopIconAnimation();
     }
 
     private void animateProgress(int progress) {

src/com/android/settings/biometrics/fingerprint/FingerprintEnrollFindSensor.java

@@ -115,10 +115,10 @@ public class FingerprintEnrollFindSensor extends BiometricEnrollBase {
 
     @Override
     protected void onStop() {
+        super.onStop();
         if (mAnimation != null) {
             mAnimation.pauseAnimation();
         }
-        super.onStop();
     }
 
     @Override