NEW YORK — A New York City carriage horse was euthanized two months after his caught-on-video collapse on a Manhattan street sparked outrage from animal rights advocates, according to the farm where it had been relocated. The horse, named Ryder, fell to the asphalt on Ninth Avenue in Hell’s Kitchen on Aug. 10 in front of crowds of bystanders, video shows. Ryder’s carriage driver was seen whipping the horse and yelling for him to get up before police and veterinarians arrived to cart the horse away. Ryder “was recently humanely euthanized due to his medical condition and age,” said a statement …