Changes to Cancel an in-flight chat stream

added the pattern ^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$ to the request property runId

added the media type application/x-www-form-urlencoded to the request body

added the media type application/json for the response with the status 400

added the media type application/json for the response with the status 401

added the media type application/json for the response with the status 403

added the media type application/json for the response with the status 404

added the non-success response with the status 500

the response property cancelled became required for the status 200

endpoint added