[bug] az iot product test does not validate command responses with Map

I'm validating a PnP device using a command with the next response

```JSON
"response": {
"@type": "CommandPayload",
"name": "diagnosticResults",
"schema": {
"@type": "Map",
"mapKey": {
"name": "key",
"schema": "string"
},
"mapValue": {
"name": "val",
"schema": "string"
}
}
}
```

The device returns a proper JSON object,

When running the `az iot product test` I got

```
"message": "{\"commandName\":\"getRuntimeStats\",\"expectedSchemaType\":\"Map\",\"actualSchemaType\":\"Unknown\",\"message\":\"Inconsistent value type. Expected type: [String], actual type: [JObject], Error code:1004, Error code:1024\",\"passed\":false,\"time\":\"2022-01-27T19:18:30.5515017+00:00\"}",
"time": "2022-01-27T19:18:30.5515017+00:00"
},
{
"message": "PnP interface commands validation failed",
"time": "2022-01-27T19:18:30.5519899+00:00"
}
```

Start by reproducing the failure with `az iot product test` using a PnP command response whose schema type is `Map` and whose device response is a JSON object. Trace the command-response validation path and compare Map handling with the reported String-versus-JObject error. Done means valid Map responses pass validation without the PnP interface command validation failure.

Written by the indexing model from the issue text.