Continuous "fireCharacteristicUpdateCallback" errors on 6.3.0
Continuous "fireCharacteristicUpdateCallback" errors on 6.3.0

I know this has been raised previously but I wasn't able to find a solution from the previous issues

### Expected Behavior
Able to see Energy values in Eve app

### Current Behavior
Lots of this: 

[3/26/2021, 11:16:05 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [Amperes]: Unable to call updateCallback
[3/26/2021, 11:16:05 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [KilowattHours]: Unable to call updateCallback
[3/26/2021, 11:16:05 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [VoltAmperes]: Unable to call updateCallback
[3/26/2021, 11:16:05 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [Volts]: Unable to call updateCallback
[3/26/2021, 11:16:05 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [Watts]: Unable to call updateCallback
[3/26/2021, 11:16:25 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [Amperes]: Unable to call updateCallback
[3/26/2021, 11:16:25 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [KilowattHours]: Unable to call updateCallback
[3/26/2021, 11:16:25 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [VoltAmperes]: Unable to call updateCallback
[3/26/2021, 11:16:25 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [Volts]: Unable to call updateCallback
[3/26/2021, 11:16:25 PM] [TplinkSmarthome] [Washing Machine] fireCharacteristicUpdateCallback [Watts]: Unable to call updateCallback


### Steps to Reproduce (for bugs)
Installed, configured and ran

### Versions
- **Node**:  12.17.0
- **Homebridge**:  1.1.1
- **OS**: Raspian
- Plug:  KASA  KP115

### Configuration

```json
{
  "platform": "TplinkSmarthome",
  "name": "TplinkSmarthome",

  "addCustomCharacteristics": true,
  "switchModels": ["KP115"],

  "discoveryPort": 0,
  "broadcast": "255.255.255.255",
  "pollingInterval": 20,
  "deviceTypes": ["plug"],

  "timeout": 100,
  "waitTimeUpdate": 100
},
```

### Homebridge Log / Command Output
as above
```
```
