Cookies made with natural colors, right, and ones made with artificial colors at a Panera Bread pop up store in New York in June 2015. (AP Photo/Mary Altaffer) MONTPELIER — The Vermont Senate abandoned a bill that would have barred a list of chemical additives from the food and drinks served in schools after two of the state’s largest school districts told lawmakers they were opposed to the proposal. Senators’ decision to scrap the bill, S.26, i…