fix: IHierarchyObject.SetParent not entering the object into the IGameManager hierarchy fixed

Engine.Core/GameManager.cs

@@ -78,6 +78,7 @@ public class GameManager : BaseEntity, IGameManager
             Remove(child);
 
         _hierarchyObjects.Remove(hierarchyObject);
+        hierarchyObject.SetParent(null);
 
         if (!hierarchyObject.ExitHierarchy())
             throw new Exception($"{hierarchyObject.Name} can't exit the hierarchy");