Caroline Vazzana doesn’t mind being called a  square .  In fact, the over-the-top tastemaker wears the cheeky nickname like a badge of honor — especially when she wears her square-shaped denims.  “These cube jeans are just so fun and unique. They’re literally wearable art,” Vazzana, 33, a Big Apple fashionista, told The Post of her $745 “Square Voluminous Jeans” from Ukrainian designer Ksenia Schnaider.  The boxy bottoms — reminiscent of those donned by cartoon dandy SpongeBob SquarePants —