VANCOUVER, British Columbia — “Glee” actor Cory Monteith, who had struggled for years with substance abuse and once said he was lucky to be alive, died of an overdose of heroin and alcohol, the British Columbia coroner’s office said Tuesday. “There is no evidence to suggest Mr. Monteith’s death was anything other than a most tragic accident,” the office said in a statement. The 31-year-old was found dead in his Vancouver, British Columbia, hotel room on Saturday after he didn’t check out on time. He was believed to be alone when he died. Hotel video and electronic records indicate he...