The last two years have been good ones for Emily Blunt, who earned major award nominations for “Oppenheimer” and “The Smashing Machine,” and co-starred in the global hit “The Devil Wears Prada 2.” But to the 43-year-old Blunt, few career milestones can compare with Steven Spielberg offering her the lead in “Disclosure Day,” in theaters now. “As a child, I remember how it churned me up and left me feeling exactly like Elliott when E.T. left,” she said recently on a video call.