Noam Galai/Getty Images for Pacsun From the mall to the Met Inside the Metropolitan Museum of Art's Great Hall, a violinist played gently in the background. The famous columns were uplit orange, and cocktail tables were covered with magenta peonies for the launch of Pacsun CEO Brieane Olson's new book, "Co Created: The Cultural Strategy That Redefined Pacsun." I'll be the first to admit that this artsy scene didn't feel like it matched the Pacsun I grew up on with its casual coastal offerings. But the Pacsun of yesteryear is a lot different from what the brand is doing today, Olson said Thursday night to hundreds of dinner guests. Today, the legacy millennial brand is speaking directly to Gen Z in hopes to "inspire the next generation and build community to create a better world at the intersection of sport, music, art, and passion," the CEO said. It's not an easy feat, and Olson knows it.…