[Core] Edit-wrap relationship capability

Wrap objects retrieved via the relationship capability
with Edit mode caching etc, for WTD-1007.

platform/commonUI/edit/src/capabilities/EditableContextCapability.js

@@ -28,7 +28,7 @@ define(
                 editableObject,
                 domainObject,
                 cache,
-                true // Not idempotent
+                true // Idempotent
             );
         };
     }