Only Kafka properties fail

> Please provide us with the following information:
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### This issue is for a: (mark with an `x`)
```
- [ x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
>
`docker run -it -e 'KafkaConnectionProperties={"bootstrap.servers=localhost:9092"}' -e DeviceCount=1000 mcr.microsoft.com/oss/azure-samples/azureiot-simulatordeviceprovisioning `

### Any log messages given by the failure
>
Environment variable for 'IotHubConnectionString' is not defined

### Expected/desired behavior
>
Simulator starts with given parameters for Kafka setup

### OS and Version?

Win 11 Home 23H2

### Versions
>

### Mention any other details that might be useful
If started without any connection parameters it acts correctly with message:
`Unhandled exception. System.Exception: Exactly one of IotHubConnectionString, EventHubConnectionString or KafkaConnectionProperties must be defined`

But when started with given: `-e 'KafkaConnectionProperties={"bootstrap.servers=localhost:9092"}'` it returns `Environment variable for 'IotHubConnectionString' is not defined`

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