SPRINGFIELD — The state’s top court doesn’t often award mulligans. And it stuck to that pattern this week by denying a plea to re-hear arguments to give unmarried couples certain legal rights.But the Illinois Supreme Court did admit a mistake was made in the case of Blumenthal v. Brewer.In a one-page order Thursday, the court explained that a paragraph in an initial version of the opinion that dismissed due process and equal protection claims was part of a draft that was never adopted by the court and …