ma's 45th—and Madonna encourages us to belt out "Happy Birthday. Singing along is Ginevra Elkann, CAA's Hylda Queally, manager Jason Weinberg and the Brant boys, 18-year-old Petey and 15-year-old Harry. HOUSE_OVERSIGHT_012743 --- PAGE BREAK --- Across the canal Luca Dini, editor of Vanity Fair Italy i