Can't add cameras to HomeKit in unbridged mode
**Describe The Problem:**
I've been using camera-ffmpeg happily for a couple of years. 

As recommended, I now want to try using it in unbridged mode.

When I switch to unbridged node, the cameras disappear from the Home app (obviously), but I am then unable to discover them and add them back as accessories. When I tell the home app to search for new accessories, it just sits there with a spinning wheel indefinitely. Nothing gets discovered.

The plugin seems to be advertising the devices ok -- see log excerpt below. There are no subsequent errors in the logs.

I've tried uninstalling and re-installing the plugin in case there's a caching issue, but it made no difference.

I saw that there was a recent issue on the same topic, but the resolution of that didn't help me.

**To Reproduce:**
Switch cameras from bridged to unbridged mode and attempt to add them to Homekit as accessories.

**Logs:**
```
Starting to advertise 'Courtyard Camera F81D' using bonjour-hap backend!
[3/2/2021, 2:17:29 PM] Courtyard Camera F81D is running on port 52100.
[3/2/2021, 2:17:29 PM] Please add [Courtyard Camera F81D] manually in Home app. Setup Code: 031-45-154
Starting to advertise 'Garden Camera DFC5' using bonjour-hap backend!
[3/2/2021, 2:17:29 PM] Garden Camera DFC5 is running on port 52101.
[3/2/2021, 2:17:29 PM] Please add [Garden Camera DFC5] manually in Home app. Setup Code: 031-45-154
Starting to advertise 'Greenhouse Camera 93D6' using bonjour-hap backend!
[3/2/2021, 2:17:29 PM] Greenhouse Camera 93D6 is running on port 52102.
[3/2/2021, 2:17:29 PM] Please add [Greenhouse Camera 93D6] manually in Home app. Setup Code: 031-45-154
Starting to advertise 'Patio Camera BC32' using bonjour-hap backend!
[3/2/2021, 2:17:29 PM] Patio Camera BC32 is running on port 52103.
[3/2/2021, 2:17:29 PM] Please add [Patio Camera BC32] manually in Home app. Setup Code: 031-45-154
Starting to advertise 'Hall Camera 794D' using bonjour-hap backend!
[3/2/2021, 2:17:29 PM] Hall Camera 794D is running on port 52104.
[3/2/2021, 2:17:29 PM] Please add [Hall Camera 794D] manually in Home app. Setup Code: 031-45-154
Starting to advertise 'Living Room Camera 641D' using bonjour-hap backend!
[3/2/2021, 2:17:29 PM] Living Room Camera 641D is running on port 52105.
[3/2/2021, 2:17:29 PM] Please add [Living Room Camera 641D] manually in Home app. Setup Code: 031-45-154
Starting to advertise 'Homebridge CAD8' using bonjour-hap backend!
```

**Homebridge Config:**

```json
{
    "name": "Camera ffmpeg",
    "cameras": [
        {
            "name": "Courtyard Camera",
            "manufacturer": "Amcrest",
            "unbridge": true,
            "videoConfig": {
                "source": "-rtsp_transport tcp -re -i rtsp://admin:Secure99@192.168.185.10",
                "stillImageSource": "-i http://admin:Secure99@192.168.185.10/cgi-bin/snapshot.cgi",
                "maxStreams": 2,
                "maxFPS": 20,
                "maxBitrate": 300,
                "vcodec": "libx264",
                "packetSize": 1316,
                "audio": false,
                "debug": false
            }
        },
        {
            "name": "Garden Camera",
            "manufacturer": "Amcrest",
            "unbridge": true,
            "videoConfig": {
                "source": "-rtsp_transport tcp -re -i rtsp://admin:Secure99@192.168.185.11",
                "stillImageSource": "-i http://admin:Secure99@192.168.185.11/cgi-bin/snapshot.cgi",
                "maxStreams": 2,
                "maxFPS": 20,
                "maxBitrate": 300,
                "vcodec": "libx264",
                "packetSize": 1316,
                "audio": false,
                "debug": false
            }
        },
        {
            "name": "Greenhouse Camera",
            "manufacturer": "Amcrest",
            "unbridge": true,
            "videoConfig": {
                "source": "-rtsp_transport tcp -re -i rtsp://admin:Secure99@192.168.185.12",
                "stillImageSource": "-i http://admin:Secure99@192.168.185.12/cgi-bin/snapshot.cgi",
                "maxStreams": 2,
                "maxFPS": 20,
                "maxBitrate": 300,
                "vcodec": "libx264",
                "packetSize": 1316,
                "audio": false,
                "debug": false
            }
        },
        {
            "name": "Patio Camera",
            "manufacturer": "Amcrest",
            "unbridge": true,
            "videoConfig": {
                "source": "-rtsp_transport tcp -re -i rtsp://admin:Secure99@192.168.185.13",
                "stillImageSource": "-i http://admin:Secure99@192.168.185.13/cgi-bin/snapshot.cgi",
                "maxStreams": 2,
                "maxFPS": 20,
                "maxBitrate": 300,
                "vcodec": "libx264",
                "packetSize": 1316,
                "audio": false,
                "debug": false
            }
        },
        {
            "name": "Hall Camera",
            "manufacturer": "Amcrest",
            "unbridge": true,
            "videoConfig": {
                "source": "-rtsp_transport tcp -re -i rtsp://admin:Secure99@192.168.185.14",
                "stillImageSource": "-i http://admin:Secure99@192.168.185.14/cgi-bin/snapshot.cgi",
                "maxStreams": 2,
                "maxFPS": 20,
                "maxBitrate": 300,
                "vcodec": "libx264",
                "packetSize": 1316,
                "audio": false,
                "debug": false
            }
        },
        {
            "name": "Living Room Camera",
            "manufacturer": "Amcrest",
            "unbridge": true,
            "videoConfig": {
                "source": "-rtsp_transport tcp -re -i rtsp://admin:Secure99@192.168.185.15",
                "stillImageSource": "-i http://admin:Secure99@192.168.185.15/cgi-bin/snapshot.cgi",
                "maxStreams": 2,
                "maxFPS": 20,
                "maxBitrate": 300,
                "vcodec": "libx264",
                "packetSize": 1316,
                "audio": false,
                "debug": false
            }
        }
    ],
    "platform": "Camera-ffmpeg"
}
```

**Environment:**

* **Node.js Version**: v14.15.5
* **NPM Version**: v6.14.11
* **Homebridge Version**: v1.3.1
* **Homebridge Camera FFmpeg Version**: v3.1.1
* **Homebridge Config UI X Plugin Version**: v4.39.1
* **Operating System**: macOS 11.2.2
