Merge branch 'development' of https://github.com/o3de/o3de into daimini/FocusMode/breadcrumbs

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.cpp

@@ -329,6 +329,11 @@ namespace AzToolsFramework
                 return AZ::Failure(AZStd::string("Could not instantiate prefab - internal error "
                                                  "(PrefabEditorEntityOwnershipInterface unavailable)."));
             }
+            if (!prefabEditorEntityOwnershipInterface->IsRootPrefabAssigned())
+            {
+                return AZ::Failure(AZStd::string("Could not instantiate prefab - no root prefab assigned. "
+                "Currently, prefabs can only be instantiated inside a level"));
+            }
 
             InstanceOptionalReference instanceToParentUnder;