Angelina Jolie and Brad Pitt’s daughter Vivienne was spotted working as an usher at the theatre. The 16-year-old theatre lover showed people to their seats at the ‘Reefer Madness: The Musical’ reunion concert in Los Angeles on July 30, after attending the opening night with her mom, according to People. The 49-year-old Hollywood actress acted as lead producer on Broadway musical ‘The Outsiders’ after Vivienne indulged her love of theatre by joining the project as a volunteer and Angelina recently admitted the teen was her toughest critic. When asked who is the “biggest theatre head” in the fam…