“Harley Quinn: Birds of Prey” – Harley Quinn (Margot Robbie) is a badass broad. Don’t take this critic’s word for it. She gave herself that moniker in “Harley Quinn: Birds of Prey”, and why not. She earned a PhD. She plays roller derby. She swings a baseball bat when trouble is afoot. She loves greasy egg sandwiches with a hearty slice of cheese, and she’s Joker’s girlfriend. Well, she was Joker’s girlfriend. Sometime after Harley Quinn’s previous big screen performance in the dreadful “Suicide Squad” (2016) – where she and…