TO BIEBS OR NOT TO BIEBS: Justin Bieber showed his allegiance to the Y-3 brand by sitting in the front row at its runway show Sunday night at Skylight at Moynihan Station. Unfortunately, the pop star wasn’t talking. Joe Manganiello of “True Blood” wasn’t as circumspect. He said Y-3 was his first runway show of the season and he took time to drive down from New Haven, where’s he’s appearing in “A Streetcar Named Desire.” What character? Stanley, of course.