refactor: remove experimental serverExternalPackages configuration

- Removed the experimental serverExternalPackages setting for 'shiki' and 'fumadocs-openapi' from the Next.js configuration file.

apps/docs-new/next.config.mjs

@@ -5,9 +5,7 @@ const withMDX = createMDX();
 /** @type {import('next').NextConfig} */
 const config = {
   reactStrictMode: true,
-  experimental: {
-    serverExternalPackages: ['shiki', 'fumadocs-openapi'],
-  },
+
 };
 
 export default withMDX(config);