added sidebar logging (#2456)

src/theme/Layout/index.js

@@ -0,0 +1,20 @@
+import React, { useEffect, useLayoutEffect } from 'react';
+import Layout from '@theme-original/Layout';
+
+export default function CustomLayout(props) {
+  useEffect(() => {
+
+    console.log('Page loaded!');
+  }, []);
+  useLayoutEffect(() => {
+    // Wait a small tick to ensure DOM is fully rendered
+    setTimeout(() => {
+      const hasSidebar = document.querySelector('.theme-doc-sidebar-container');
+      if (!hasSidebar) {
+        console.log("doesn't have sidebar")
+        Statsig.instance().logEvent('NoSidebarPageLoad', window.location.href);
+      }
+    }, 0);
+  }, []);
+  return <Layout {...props} />;
+}