docs: update universal example (#48665)

This change updates the universal example to align with latest CLI changes.

PR Close #48665

aio/content/examples/universal/server.ts

@@ -1,15 +1,15 @@
 import 'zone.js/node';
 
+import { APP_BASE_HREF } from '@angular/common';
 import { ngExpressEngine } from '@nguniversal/express-engine';
 import * as express from 'express';
+import { existsSync } from 'fs';
 import { join } from 'path';
 
 import { AppServerModule } from './src/main.server';
-import { APP_BASE_HREF } from '@angular/common';
-import { existsSync } from 'fs';
 
 // The Express app is exported so that it can be used by serverless Functions.
-export function app() {
+export function app(): express.Express {
   const server = express();
   const distFolder = join(process.cwd(), 'dist/browser');
   const indexHtml = existsSync(join(distFolder, 'index.original.html')) ? 'index.original.html' : 'index';
@@ -48,8 +48,8 @@ export function app() {
   return server;
 }
 
-function run() {
-  const port = process.env.PORT || 4000;
+function run(): void {
+  const port = process.env['PORT'] || 4000;
 
   // Start up the Node server
   const server = app();

aio/content/examples/universal/src/main.server.ts

@@ -1,9 +1 @@
-import { enableProdMode } from '@angular/core';
-
-import { environment } from './environments/environment';
-
-if (environment.production) {
-  enableProdMode();
-}
-
 export { AppServerModule } from './app/app.server.module';

aio/content/examples/universal/tsconfig.server.json

@@ -2,14 +2,9 @@
   "extends": "./tsconfig.app.json",
   "compilerOptions": {
     "outDir": "./out-tsc/app-server",
-    "module": "commonjs",
     "types": ["node"]
   },
   "files": [
-    "src/main.server.ts",
     "server.ts"
-  ],
-  "angularCompilerOptions": {
-    "entryModule": "./src/app/app.server.module#AppServerModule"
-  }
+  ]
 }