Filmmakers Mona Fastvold and Brady Corbet are clearly fascinated by ambition. They’re fascinated, too, by dreamers — difficult dreamers, brilliant but demanding people who have plans they must fulfill no matter the personal cost. Movie Review: In ‘Testament of Ann Lee,’ a blazing Amanda Seyfried can make you believe anything They’re also interested in dreamers who cross the ocean to America with these difficult, lofty plans. And, finally, they find singular actors to play these roles. You could say the couple, artistic and life partners, is on a roll. They together made “The Brutalist” last year,directed by Corbet and co-written with Fastvold, which won Adrien Brody an Oscar. And now, with Fastvold directing, we have “The Testament of Ann Lee” — a stirring and, yes, difficult movie that features a blazing Amanda Seyfried as the Shaker leader. It’s a performance that will knock your 18th-century socks off. There are, of course, key differences. For one thing, unlike fictional architect Lázló Tóth in “The Brutalist,” Ann Lee was a real person — a woman whose life …