Bug: Ambient light level calculation
### Describe The Bug

A light level of 2 results in an ambient light level of 666.6666666666666 and causes a rounding issue in the Homebridge UI. The Home app rounds the value to 667. This is probably unrelated, but in the Home app, the light level only appears when the room is selected and not when "Home" is selected but other switches and readings appear in both areas.

### To Reproduce

Ensure that the light level is 2.

### Expected behavior

For the calculation to be rounded or calculated correctly.

### Relevant log output

```shell
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain BLE parseStatus
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain CurrentPosition 100
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain Standby, CurrentPosition: 100
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain Stopped
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain CurrentPosition: 100, TargetPosition: 100, PositionState: 2,
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain LightLevel: 2, Calculation: 666.6666666666666
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain LightLevel: 2, CurrentAmbientLightLevel: 666.6666666666666
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain BatteryLevel: 63, StatusLowBattery: 0
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain updateCharacteristic CurrentPosition: 100
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain updateCharacteristic PositionState: 2
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain updateCharacteristic TargetPosition: 100
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain updateCharacteristic CurrentAmbientLightLevel: 666.6666666666666
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain updateCharacteristic BatteryLevel: 63
[20/02/2022, 17:00:26] [SwitchBot] [DEBUG] Curtain: Curtain updateCharacteristic StatusLowBattery: 0
```


### Config for homebridge-switchbot

```shell
{
            "name": "SwitchBot",
            "credentials": {
                "notice": "Keep your token a secret!"
            },
            "options": {
                "devices": [
                    {
                        "deviceId": "XXX",
                        "configDeviceName": "Curtain",
                        "configDeviceType": "Curtain",
                        "ble": true,
                        "curtain": {
                            "set_min": 10,
                            "set_max": 90
                        },
                        "logging": "debug"
                    }
                ],
                "irdevices": [
                    {
                        "logging": "standard"
                    }
                ],
                "logging": "standard"
            },
            "platform": "SwitchBot"
        }
    ],
```


### Screenshots

![PixelSnap 2022-02-20 at 17 42 10@2x](https://user-images.githubusercontent.com/2276355/154855322-cb9345ab-ee3a-4df5-8f3f-9d17d873eead.png)
![PixelSnap 2022-02-20 at 17 45 41@2x](https://user-images.githubusercontent.com/2276355/154855324-894e6418-6a35-4de7-8c78-f0dca98d7f61.png)


### Device & Model

SwitchBot Curtain W0701600

### Node.js Version

v14.18.3

### NPM Version

v6.14.15

### Homebridge Version

v1.4.0

### Homebridge Switchbot Plugin Version

v1.12.5

### Homebridge Config UI X Plugin Version

v4.42.0

### Operating System

Raspian