Approve a draft message

curl --request POST \
  --url https://api.helpyousponsor.com/v1/admin/message/draft/{email_id}/approve \
  --header 'Content-Type: application/json' \
  --data '
{
  "entity_id": 123,
  "donor_id": 123
}
'

{
  "message": "<string>"
}