A defendant is reportedly cooperating with Arizona prosecutors in the “fake electors” case over alleged illegal efforts to overturn former President Donald Trump’s 2020 loss to President Joe Biden. During a taping of the TV program “Sunday Square Off,” State Attorney General Kris Mayes said she planned to make a “very significant announcement” early this week about the case, the 12News website reported Friday. When asked if that meant one of the 18 defendants was going to flip, Mayes reportedly said: “I think that’s accurate.” Mayes declined to elaborate but added: “We’re making progress in th…