Authorities have confirmed a seat previously held by Progressive Conservative Party of Ontario MPP Caroline Mulroney has been vacated after the former cabinet minister resigned. Elections Ontario staff said in accordance with provincial law, a byelection must be called by Dec. 2 at the latest. According to the Legislative Assembly Act, the earliest election day in the York–Simcoe riding is July 9 and the latest is Dec. 31. Mulroney, who was firs…