preload custom wizard start script

assets/javascripts/custom-wizard-start.js

@@ -0,0 +1,4 @@
+(function() {
+  var wizard = require('discourse/plugins/discourse-custom-wizard/wizard/custom-wizard').default.create();
+  wizard.start();
+})();

plugin.rb

@@ -17,6 +17,7 @@ if Rails.env.production?
     wizard-custom-lib.js
     wizard-custom.js
     wizard-plugin.js
+    wizard-start.js
     stylesheets/wizard/wizard_custom.scss
     stylesheets/wizard/wizard_composer.scss
     stylesheets/wizard/wizard_variables.scss

views/layouts/wizard.html.erb

@@ -39,11 +39,6 @@
       <%= raw theme_lookup("body_tag") %>
     <%- end %>
 
-    <script>
+    <%= preload_script 'custom-wizard-start' %>
-      (function() {
-        var wizard = require('discourse/plugins/discourse-custom-wizard/wizard/custom-wizard').default.create();
-        wizard.start();
-      })();
-    </script>
   </body>
 </html>