fix: update serverComponentExternalPackages references to latest Next.js docs links

Author: tiffanynwyeung

src/pages/[platform]/build-a-backend/server-side-rendering/index.mdx

@@ -251,7 +251,7 @@ const nextConfig = {
 };
 ```
 
-See Next.js documentation on [`serverComponentsExternalPackages`](https://nextjs.org/docs/app/api-reference/next-config-js/serverComponentsExternalPackages) for more details.
+See Next.js documentation on [`serverComponentsExternalPackages`](https://nextjs.org/docs/app/api-reference/config/next-config-js/serverExternalPackages) for more details.
 </Callout>
 
 ### With Next.js App Router

src/pages/gen1/[platform]/build-a-backend/server-side-rendering/nextjs/index.mdx

@@ -253,7 +253,7 @@ const nextConfig = {
 };
 ```
 
-See Next.js documentation on [`serverComponentsExternalPackages`](https://nextjs.org/docs/app/api-reference/next-config-js/serverComponentsExternalPackages) for more details.
+See Next.js documentation on [`serverComponentsExternalPackages`](https://nextjs.org/docs/app/api-reference/config/next-config-js/serverExternalPackages) for more details.
 </Callout>
 
 ### With Next.js App Router