Fix potential item change in background thread

LeStorage/StoredCollection.swift

@@ -433,8 +433,10 @@ public class StoredCollection<T: Storable>: RandomAccessCollection, SomeCollecti
         Task {
             do {
                 if let result = try await self._store.sendInsertion(instance) {
+                    DispatchQueue.main.async {
                         self._hasChanged = instance.copyFromServerInstance(result)
                     }
+                }
             } catch {
                 Logger.error(error)
             }