Lady Gaga used her experience with “mania and chaos inside” to inform her performance of Harley Quinn. The 38-year-olod actress portrays the comic book character in ‘Joker: Folie à Deux’ and she’s explained how she drew on her personal way of handling feelings of being overwhelmed to develop a “quietness” for her alter ego. She told the new issue of America’s Vogue magazine: “Harley Quinn is a character people know from the ether of pop culture. “I had a different experience creating her, namely my experience with mania and chaos inside — for me, it creates a quietness. “Sometimes women are la…