DOP-3499: concatenate associated children when merging node (#762)

* concatenate associated children when merging node

* DOP-3499: follow up - add different versions in test data (#763)

* update snapshots

* add awaits for async fn in test setups

* add actual different versions in mocked json

Author: seungpark

modules/persistence/src/services/metadata/ToC/index.ts

@@ -75,7 +75,7 @@ const mergeNode = (node: ToC, tocs: ToCInsertions, currentProject) => {
       };
       return originalNode;
     });
-    return copiedChildren;
+    return children.concat(copiedChildren);
   }, []);
   return node;
 };