Margot Robbie's Harley Quinn was the unequivocal breakout from 2016's infamously troubled Suicide Squad. David Ayer's 2016 antihero team-up movie took heat from fans and critics alike, but if there was one thing everyone agreed on, it was that Robbie stole the show as the fan-favorite Harley Quinn in the character's long-awaited big-screen debut. With next year's Birds of Prey And the Fantabulous Emancipation of One Harley Quinn Robbie's scene-stealer shakes off the Skwad entirely -- not to mention her powerfully terrible paramour Mistah Jay -- with an R-rated girl …