MC-17823: Access Images/Widgets/Variable from HTML content type

- fix ie11

Author: anthoula

app/code/Magento/PageBuilder/view/adminhtml/web/js/form/element/html-code.js

@@ -9,7 +9,7 @@ define([
 ], function (Textarea) {
     'use strict';
 
-    const HTML_ID_PLACEHOLDER = 'HTML_ID_PLACEHOLDER';
+    var HTML_ID_PLACEHOLDER = 'HTML_ID_PLACEHOLDER';
 
     return Textarea.extend({
         defaults: {