Nicola Coughlan gave a masterclass in accents in a new video promoting the third season of Netflix’s hit period drama “Bridgerton.” Fans commenting on YouTube hailed the Irish actor — who plays Penelope Featherington in the show — as “genius.” Coughlan effortlessly switched between her usual “soft” Galway accent to mimic people from Derry, Dublin and Cork in the clip. She also imitated the Kardashian vocal fry as she explained the difference in accents and lifted the lid on the subtle shift in her character’s tone since the first season…