Merge pull request #9640 from umbraco/v8/bugfix/memory-leak-9348

Fixes a memory leak caused by deep cloning

(cherry picked from commit 824349ae0d)

src/Umbraco.Core/Models/PropertyCollection.cs

@@ -168,6 +168,8 @@ namespace Umbraco.Core.Models
         /// </summary>
         public event NotifyCollectionChangedEventHandler CollectionChanged;
 
+        public void ClearCollectionChangedEvents() => CollectionChanged = null;
+
         protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs args)
         {
             CollectionChanged?.Invoke(this, args);