Fix error handling in layout server file and add console log in layout svelte file

src/routes/+layout.svelte

@@ -14,6 +14,8 @@
   if (data.usingVercel === "true") {
     inject();
     injectSpeedInsights();
+  } else {
+    console.log("Not using Vercel");
   }
 
   let isServerSetup = data.isServerSetup;