Fix connector type checker

[sshplendid]

I'm using Kafka connect with 2.8.0 version and found that the connect topology visualization and the connector count on dashboard is something wrong.

• I'm using both source and sink connectors, however, the dashboard shows only sink connectors' count.

The connector type can be recognized by $.type field Since Confluent Kafka 6.2.1
This resolves the Connect topology visualization and connectors' count on the dashboard at cluster home page

https://docs.confluent.io/platform/6.2.1/connect/references/restapi.html#connectors

request

GET /connectors/{{connector-name}} HTTP/1.1
Content-Type: application/json

response

{
    "name": "connector-name",
    "config": {    },
    "tasks": [    ],
    "type": "source" // here
}

• wrong (current)

• good (after applying this pr)