chore: explicitly skip the Vercel OTEL when running open-next (#8833)

Author: dario-piotrowicz

apps/site/instrumentation.ts

@@ -1,5 +1,7 @@
-import { registerOTel } from '@vercel/otel';
-
-export function register() {
-  registerOTel({ serviceName: 'nodejs-org' });
+export async function register() {
+  if (!('Cloudflare' in globalThis)) {
+    // Note: we don't need to set up the Vercel OTEL if the application is running on Cloudflare
+    const { registerOTel } = await import('@vercel/otel');
+    registerOTel({ serviceName: 'nodejs-org' });
+  }
 }