SpatializerHelper: implement onOutputChanged() method

Add implementation of onOutputChanged() method to
I NativeSpatializerCallback.
Empty implementaiton with just log for now.

Test: run and enable/disable spatial audio
Bug: 202723925
Change-Id: I81ffd099e5f2cf1269fbde141b010d792917da29

services/core/java/com/android/server/audio/SpatializerHelper.java

@@ -213,6 +213,10 @@ public class SpatializerHelper {
                 postInitSensors(true);
             }
         }
+
+        public void onOutputChanged(int output) {
+            logd("SpatializerCallback.onOutputChanged output:" + output);
+        }
     };
 
     // spatializer head tracking callback from native