This fathead serial prankster just can’t help himself, getting up inside a sheer outer layer of actress America Ferrera’s dress Friday at Cannes, leaving her shocked and stunned. The “Sisterhood of the Traveling Pants” star, 30, looked glamorous while posing in front of a sea of photographers with her “How to Train Your Dragon 2” co-stars when journo Vitalii Sediuk dived onto the red carpet and weaseled his head under her puffy white ball gown. A freaked-out Ferrera and “Dragon” co-stars Cate Blanchett and Kit Harington looked appalled as security guards grabbed him and hauled him away. Sediuk is notorious...