Revert "Refactor BiometricEnrollBase::onStop()"

This reverts commit 6b6d8c0d6d.

Reason for revert: Should use shouldFinishWhenBackgrounded() to
control the behavior during onStop()

Bug: 197717071
Change-Id: I6aeacd5fb0d4400911a2e3d1567db660a0f1798a

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

@@ -181,6 +181,16 @@ public abstract class BiometricEnrollBase extends InstrumentedActivity {
         getWindow().setStatusBarColor(getBackgroundColor());
     }
 
+    @Override
+    protected void onStop() {
+        super.onStop();
+        if (!isChangingConfigurations() && shouldFinishWhenBackgrounded()
+                && !BiometricUtils.isAnyMultiBiometricFlow(this)) {
+            setResult(RESULT_TIMEOUT);
+            finish();
+        }
+    }
+
     protected boolean shouldFinishWhenBackgrounded() {
         return !WizardManagerHelper.isAnySetupWizard(getIntent());
     }