Return the list of consumer groups.

curl --request GET \
  --url https://api.example.com/admin/v1/consumer-groups

{
  "data": [
    {
      "consumer_group_id": "<string>",
      "partition_assignor": "<string>",
      "state": "<string>",
      "type": "<string>",
      "metadata": {},
      "simple": true,
      "kind": "<string>"
    }
  ],
  "metadata": {},
  "kind": "<string>"
}