Custom services not displayed
I am having issues creating custom service while implementing homebridge plugin.

I used https://github.com/homebridge/homebridge-plugin-template as a starting point, and everything works fine - all functions within documentation and documented services - all good.

However, I am struggling to display custom service.

Based on the check i performed by checking currently created plugins or older threads with similar questions, creating custom service and custom characteristics seems relatively simple.

For example, in my case, this is the file which would create both of these:

```javascript
import { Characteristic, Service, Perms, Formats, Units } from 'hap-nodejs';

export class Delay extends Characteristic {
    static readonly UUID: string = '000000A4-0000-1000-8000-0026BB765298';

    constructor() {
      super('Delay', Delay.UUID);
      this.setProps({
        format: Formats.UINT32,
        maxValue: 10000000,
        minValue: 0,
        minStep: 0.1,
        unit: Units.SECONDS,
        perms: [Perms.PAIRED_READ, Perms.PAIRED_WRITE, Perms.NOTIFY],
      });
      this.value = this.getDefaultValue();
    }
}

export class Ping extends Service {
    static UUID = '00000085-0000-1000-8000-0026BB765215';
    
    constructor(displayName: string, subtype?: string) {
      super(displayName, Ping.UUID, subtype);

      this.addCharacteristic(Delay)
      this.addOptionalCharacteristic(Characteristic.Name);
    }
}
```

And then within accessory, simply:
```javascript
const customPing = this.accessory.getService('Ping test') ||
        this.accessory.addService(Ping, 'Ping test', 'UniqueIdentifier-qasdasfdgs');
console.log(Ping);
```

And this works fine. No error is throwned, console indicate that we have service with proper characteristis etc ... However, this service is not displayed on phone side, nor within ui of homebridge-config-ui-x.

Do you have any ideas what im doign wrong here?

