chore: split sampleRUM code

Author: kptdobe

404.html

@@ -11,8 +11,6 @@
   <meta property="og:title" content="Page not found">
   <script src="/scripts/scripts.js" type="module" crossorigin="use-credentials"></script>
   <script type="module">
-    import { sampleRUM } from '/scripts/aem.js';
-
     window.addEventListener('load', () => {
       if (document.referrer) {
         const { origin, pathname } = new URL(document.referrer);
@@ -26,9 +24,12 @@
           btnContainer.append(backBtn);
         }
       }
-      sampleRUM('404', { source: document.referrer });
     });
   </script>
+  <script type="module">
+    import { sampleRUM } from '/scripts/aem.js';
+    sampleRUM('404', { source: document.referrer });
+  </script>
   <link rel="stylesheet" href="/styles/styles.css">
   <style>
     main.error {