Changes to Update drop item

the response property description became nullable for the status 200

the response property external_url became nullable for the status 200

the response property name became nullable for the status 200

added the new optional request property animation_url

added the media type */* for the response with the status 400

added the media type */* for the response with the status 403

added the media type */* for the response with the status 404

added the optional property animation_url to the response with the 200 status

added the optional property code to the response with the 409 status