Send message

curl --request POST \
  --url https://workflow.botstacks.ai/assistant/{botstackId}/message \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <x-api-key>' \
  --data '{
  "waitForResponse": true,
  "message": "<string>",
  "userId": "<string>"
}'