Add logging for SlicePreferenceController

Test: verify logging when slice is updated
Bug: 335872142
Bug: 339887313
Change-Id: I2173663beae2a482a9d3bdcec3c2270a2f3733cc

src/com/android/settings/slices/SlicePreferenceController.java

@@ -92,6 +92,7 @@ public class SlicePreferenceController extends BasePreferenceController implemen
     @Override
     public void onChanged(Slice slice) {
         mSlicePreference.onSliceUpdated(slice);
+        Log.w(TAG, "Slice UI updated, uri: " + mUri + ", slice content: " + slice);
     }
 
     private void removeLiveDataObserver() {