Cannot POST /login using latest version

New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest versions of Parse Server and Parse Dashboard.

Issue Description

Setup new server with latest parse-server and parse-dashboard results in the below screenshot error.

Latest version of dashboard

I am using express and the using the following to init parse-dashboard:

var dashboard = new ParseDashboard({
  "apps":dashboards,
  "iconsFolder": "icons",
  "users": [
    {
      "user":"username",
      "pass":"password"
    }
  ],
  "useEncryptedPasswords": false,
  "trustProxy": 1
},true);

var app = express();
app.use(helmet());
app.set('view engine', 'pug');
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use('/parse', api);
console.log(servers[0]);
for (var i = 0; i < servers.length; i++) {
    //Add clients
  app.use('/parse', servers[i]);
}

app.use('/dashboard/', dashboard);

dashboards above is an array of objects.

Steps to reproduce

Actual Outcome

I see Cannot POST /login

Expected Outcome

Dashboard apps shown

Environment

├── @parse/fs-files-adapter@1.2.1
├── @parse/s3-files-adapter@1.6.2
├── @parse/simple-mailgun-adapter@2.0.0
├── bcrypt@5.0.1
├── express@4.17.3
├── helmet@5.0.2
├── parse-dashboard@4.0.1
├── parse-server-mailgun-adapter-template@1.1.7
├── parse-server-onesignal-push-adapter@1.0.0
└── parse-server@5.0.0

Dashboard

• Parse Dashboard version: 4.0.1
• Browser (Safari, Chrome, Firefox, Edge, etc.): Safari, Brave
• Browser version: 1.36.112 Chromium: 99.0.4844.51](https://brave.com/latest/)

Server

• Parse Server version: 5.0.0
• Operating system: Debian 10
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): Local

Database

• System (MongoDB or Postgres): MongoDB
• Database version: 5.0.0
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): Local

Logs

Start with the ParseDashboard initialization and the Express app.use('/dashboard/', dashboard) mount shown in the report. Reproduce the login request with Parse Dashboard 4.0.1 and Parse Server 5.0.0, then trace whether POST /login reaches the mounted dashboard. Done means the login succeeds and the dashboard apps are shown.