added compiler directives to fix build issue

com.unity.perception/Runtime/GroundTruth/Labeling/Labeling.cs

                 .RefreshLabeling(m_Entity);
         }
 
+        #if UNITY_EDITOR
         /// <summary>
         /// Get the path of the given asset in the project, or get the path of the given Scene GameObject's source prefab if any
         /// </summary>
 
             return assetPath;
         }
+        #endif
+#if UNITY_EDITOR
     /// <summary>
     /// A labeling scheme based on which an automatic label can be produced for a given asset. E.g. based on asset name, asset path, etc.
     /// </summary>
             return stringList.Count > 1 ? stringList[stringList.Count-2] : null;
         }
     }
+    #endif
 }