much-ballyhooed “One Night Only” concert Sunday on CBS, the 15-time Grammy Award winner set the scene for a Los Angeles man named Quentin Brunson to pop the question to his unsuspecting girlfriend of seven years, Ashleigh Mann. “I need every person to be really bloody quiet, alright?” whispered an excited Adele, 33, to her star-studded audience at the landmark Griffith Observatory in LA. “If you make a noise, I’m going to kill you,” the British bombshell jokingly threatened before instructing