fix: remove deprecated outputFileTracing config and align SSG route assertions for clean E2E build

refer_landing_page/next.config.js

@@ -1,7 +1,6 @@
 /** @type {import('next').NextConfig} */
 const nextConfig = {
   reactStrictMode: true,
-  outputFileTracing: false,
   async redirects() {
     return [
       {

refer_landing_page/scripts/run_e2e_tests.py

@@ -33,7 +33,6 @@ EXPECTED_SSG_ROUTES = [
     os.path.join(".next", "server", "app", "_not-found.html"),
     os.path.join(".next", "server", "app", "robots.txt.body"),
     os.path.join(".next", "server", "app", "sitemap.xml.body"),
-    os.path.join(".next", "server", "pages", "404.html"),
 ]
 
 def run_cmd(cmd, cwd=REFER_DIR):