FIX: confine the wizard composer's dropZone

assets/javascripts/wizard/components/wizard-composer-editor.js.es6

@@ -88,6 +88,12 @@ export default ComposerEditor.extend({
   _bindUploadTarget() {
     this._super(...arguments);
     const $element = $(this.element);
+    // adding dropZone property post initialization
+    $element.fileupload(
+      'option',
+      'dropZone',
+      $element
+    );
 
     $element.off("fileuploadsubmit");