MC-3653: Can Drag & Drop Child Content Types Into Hidden Content Types

- Fix issue of dragging from panel into hidden content

Author: davemacaulay

app/code/Magento/PageBuilder/view/adminhtml/web/js/drag-drop/sortable.js

@@ -8,7 +8,6 @@ import ContentTypeCollectionInterface from "./content-type-collection.d";
 import ContentTypeInterface from "./content-type.d";
 import { moveArrayItemIntoArray, removeArrayItem } from "./utils/array";
 
-
 /**
  * @api
  */

app/code/Magento/PageBuilder/view/adminhtml/web/ts/js/collection.ts

@@ -168,7 +168,7 @@ function onSortStop(preview: Preview, event: Event, ui: JQueryUI.SortableUIParam
         events.trigger("stage:interactionStop");
     }
 
-    if (ui.item && sortedContentType === null) {
+    if (ui.item && !sortedContentType) {
         ui.item.remove();
     }