Redis liveQueryPublisher connection not closed on shutdown

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 version of Parse Server.

Issue Description

Hello! 👋 I am having a need to handle graceful shutdown in an application, and I found the handleShutdown method inside the ParseServer class.

Using this method works great when only using MongoDB (and even a cache/file adapters) but breaks down whenever I set up a redisURL inside the liveQuery configuration, which is necessary for our use case (we need it to handle Parse inside a k8s cluster).

Digging deeper, I found that the liveQueryController creates a publisher with a RedisPubSub instance when instantiating ParseServer, but it's never disconnected from during shutdown (because its corresponding controller is not referenced inside the ParseServer class).

Steps to reproduce

Run the following code, having MongoDB and Redis instances started and listening in their default ports beforehand. The following code provides a minimal reproduction of the issue (I can provide a minimal repo reproducing the issue if necessary)

const { ParseServer } = require('parse-server');

const parseServer = ParseServer.start({
  appId: 'someAppId',
  masterKey: 'someMasterKey',
  databaseURI: 'mongodb://127.0.0.1:27017',
  liveQuery: {
    redisURL: 'redis://127.0.0.1:6379',
  },
  serverStartComplete: async () => {
    parseServer.server.close(); // Closes http server
    await parseServer.handleShutdown(); // Successfully disconnects from DB, but not from Redis
    console.log('Node process is left hanging indefinitely, connected to Redis');
  },
});

Actual Outcome

The process is left hanging indefinitely, instead of correctly handling shutdown; even when a SIGINT is sent.

Expected Outcome

The process is expected to exit (with status 0), in the same way it exits when only using the database configuration. The following code (without the liveQuery configuration) works just as expected:

const { ParseServer } = require('parse-server');

const parseServer = ParseServer.start({
  appId: 'someAppId',
  masterKey: 'someMasterKey',
  databaseURI: 'mongodb://127.0.0.1:27017',
  serverStartComplete: async () => {
    parseServer.server.close();
    await parseServer.handleShutdown();
    console.log('Node process exits after this callback!');
  },
});

Failing Test Case / Pull Request

• 🤩 I submitted a PR with a fix and a test case.
• 🧐 I submitted a PR with a failing test case.

Environment

Server

• Parse Server version: 4.5.0
• Operating system: Mac OS (also tested on Ubuntu 18.04 LTS)
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): N/A

Database

• System (MongoDB or Postgres): MongoDB
• Database version: 4.4.5
• Redis version: 6.2.2
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): N/A

Client

• SDK (iOS, Android, JavaScript, PHP, Unity, etc): N/A
• SDK version: N/A

Logs

No relevant logs to show.

The issue points to ParseServer.handleShutdown, liveQueryController, and RedisPubSub; start there and inspect the failing test case submitted with the issue. Confirm the shutdown path disconnects the liveQuery Redis publisher and that the reproduction exits cleanly with status 0. Done means the Redis connection no longer keeps the Node process alive.