Downvote a comment on behalf of the authenticated user
downvotes array. Removes the user from upvotes if they had previously upvoted. Reduces the reputation of the comment’s author.
Missing Comment ID - 400 Bad Request
Not Found - 404 Not Found
Already Downvoted - 409 Conflict
Server Error - 500 Internal Server Error
upvotes if it was previously added.409 Conflict is returned if the user has already downvoted the comment.