Add agent to channel

curl --request POST \
  --url http://localhost:3000/api/messaging/central-channels/{channelId}/agents \
  --header 'Content-Type: application/json' \
  --data '{
  "agentId": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
}'

{
  "success": true,
  "message": "<string>"
}