### Apache Airflow version

2.2.3 (latest released)

### What happened

When I modify airflow.cfg about default webserver listening port to 8000,  then start with "airflow standalone"

A error will be printed:
 webserver | [2021-12-25 22:20:08 +0800] [16173] [ERROR] Connection in use: ('0.0.0.0', 8080)
 webserver | [2021-12-25 22:20:08 +0800] [16173] [ERROR] Retrying in 1 second.
 webserver | [2021-12-25 22:20:10 +0800] [16173] [ERROR] Connection in use: ('0.0.0.0', 8080)
 webserver | [2021-12-25 22:20:10 +0800] [16173] [ERROR] Retrying in 1 second.
 webserver | [2021-12-25 22:20:11 +0800] [16173] [ERROR] Connection in use: ('0.0.0.0', 8080)
 webserver | [2021-12-25 22:20:11 +0800] [16173] [ERROR] Retrying in 1 second.
 webserver | [2021-12-25 22:20:12 +0800] [16173] [ERROR] Connection in use: ('0.0.0.0', 8080)
 webserver | [2021-12-25 22:20:12 +0800] [16173] [ERROR] Retrying in 1 second.
 webserver | [2021-12-25 22:20:13 +0800] [16173] [ERROR] Connection in use: ('0.0.0.0', 8080)
 webserver | [2021-12-25 22:20:13 +0800] [16173] [ERROR] Retrying in 1 second.
 webserver | [2021-12-25 22:20:14 +0800] [16173] [ERROR] Can't connect to ('0.0.0.0', 8080)

Source code position,
https://github.com/apache/airflow/blob/main/airflow/cli/commands/standalone_command.py line 209, function is_ready
        return self.port_open(**8080**) and self.job_running(SchedulerJob) and self.job_running(TriggererJob)

force the port to 8080, it's wrong.

### What you expected to happen

_No response_

### How to reproduce

_No response_

### Operating System

All System

### Versions of Apache Airflow Providers

_No response_

### Deployment

Other

### Deployment details

_No response_

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

airflow/cli/commands/standalone_command.py
elif user_exists and we_know_password:
            with open(password_path) as file:
                password = file.read().strip()
        
        else:
            password = None
        
        self.user_info = {"username": "admin", "password": password}
    def is_ready(self):
        """
        Detects when all Airflow components are ready to serve.
        For now, it's simply time-based.
        """
        return self.port_open(8080) and self.job_running(SchedulerJob) and self.job_running(TriggererJob)
    def port_open(self, port):
        """
        Checks if the given port is listening on the local machine.
        (used to tell if webserver is alive)
        """
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            sock.settimeout(1)
            sock.connect(("127.0.0.1", port))
            sock.close()
        except (OSError, ValueError):
            
            return False
        return True
    def job_running(self, job):