Fix the settings crash when SimDialogActivity is null

The PreferredSimDialogFragment did updateDialog after SimDialogActivity
was finished. It caused the settings crash. This is similar to b/184899699

Bug: 220803944
Test: build pass
Change-Id: I9a5964400a63053e362632944b9e7aa8ec1bbea8

src/com/android/settings/sim/SimDialogFragment.java

@@ -83,6 +83,12 @@ public abstract class SimDialogFragment extends InstrumentedDialogFragment imple
         }
     }
 
+    @Override
+    public void dismiss() {
+        mChangeListener.stop();
+        super.dismiss();
+    }
+
     public abstract void updateDialog();
 
     @Override