She was a hard-partying, drug-using, club-going, shameless flirt who spent money like it was going out of style and beamed as she was photographed naked in a pile of cash — but a California mom long ago convicted of murder insists she’s no killer. Mary Ellen Samuels — known for orchestrating the murders-for-hire of her ex-husband Robert and a hitman who allegedly helped do him in — says in newly filed court papers that her 1994 trial was “fundamentally unfair” because prosecutors slut-shamed