Should provide a way to handle if the MQTT broker responses a CONNACK with failure error code

[terry-xiaoyu]

Describe the bug

For now if the SDK fails to connect to the broker because of AUTH failed, it will automatically reconnect the underlying MQTT connection, but the top layer MCP application cannot know the connection status.

Expected behavior

• Provide a way to update and get the MQTT connection status.
• Handle the CONNACK with error codes other than 0 (success)
• Don't automatically reconnect if:
  • auth failed
  • another client connected with the same clientid