Merge remote-tracking branch 'origin/fix/pagebuilder-render-slow' into prpb854

Author: glo24157

app/code/Magento/PageBuilder/view/adminhtml/web/template/page-builder.html

@@ -31,6 +31,6 @@
         <with args="stage">
             <render></render>
         </with>
-        <iframe attr="id: 'render_frame_' + id" sandbox="allow-scripts" style="position: absolute; width:0; height:0; border: none;"></iframe>
+        <iframe attr="id: 'render_frame_' + id" sandbox="allow-scripts allow-same-origin" style="position: absolute; width:0; height:0; border: none;"></iframe>
     </if>
 </div>