Dont wake after shutdown
### Issue

I will explain it in the best possible way:

The computer can ALWAYS be turned on if I turn it off manually. If I turn it off using this plugin, It can't turn it on. I have been able to verify that this is most probably plugin's fault, because if I run the SSH command to turn it off manually, the plugin can then turn on the PC.

I am going to pass a series of LOGS that I have been able to compile proving that it is the fault of this plugin:

These logs are from when I shut down the computer with homebridge:

![image](https://github.com/AlexGustafsson/homebridge-wol/assets/22009615/c53cfa2f-2341-469e-8540-648ad51c9111)

The problem comes, that the plugin stays stuck until I don't turn PC on manually, which is when the log that I mark below appears:

![image](https://github.com/AlexGustafsson/homebridge-wol/assets/22009615/dd035092-0da3-4f80-ba70-244754e60df2)

Until the "Waiting for shutdown grace time" appears, the plugin becomes unresponsive, and it doesn't appear until I turn on the PC manually. No matter how much I click on the homekit switch to turn on the computer, no logs appear.

If I turn the PC off manually, I can turn it on and the logs appear as they should:

![image](https://github.com/AlexGustafsson/homebridge-wol/assets/22009615/12977034-a63e-4eee-9207-eac51d12624b)

See if anyone can help me.

### Environment

```Markdown
- os and os version: Raspbian GNU/Linux Bullseye (11)
- node version: 20.10.0
- homebridge version: 1.7.0
- homebridge-wol version: 6.0.1
```


### Configuration

{
    "name": "Ordenador",
    "manufacturer": "homebridge-wol",
    "model": "NetworkDevice",
    "host": "192.168.5.136",
    "pingInterval": 5,
    "pingsToChange": 1,
    "pingTimeout": 1,
    "pingCommandTimeout": 0,
    "mac": "XX:XX:XX:XX:XX:XX",
    "broadcastAddress": "192.168.5.255",
    "startCommand": "wakeonlan XX:XX:XX:XX:XX:XX",
    "startCommandTimeout": 0,
    "wakeGraceTime": 30,
    "wakeCommandTimeout": 0,
    "shutdownCommand": "ssh lechucico@192.168.5.136 shutdown -h",
    "shutdownGraceTime": 30,
    "shutdownCommandTimeout": 0,
    "logLevel": "None",
    "returnEarly": true,
    "accessory": "NetworkDevice"
}