Finalized theme loading and stuff

app/javascript/core/embed.js

@@ -13,7 +13,7 @@ window.addEventListener('message', e => {
       id: data.id,
       height: document.getElementsByTagName('html')[0].scrollHeight,
     }, '*');
-  });
+  };
 
   if (['interactive', 'complete'].includes(document.readyState)) {
     setEmbedHeight();