James McClain Though they bought their current Beverly Hills residence barely 18 months ago, music phenom Justin Bieber and his model wife Hailey Baldwin have already scratched the itch to upgrade, shelling out millions for a supersized 90210 house in a particularly celebrity-infested neighborhood.Sited high in the mountains above Beverly Hills, the new Bieber-Baldwin estate lies within the illustrious Beverly Park, the guard-gated community known for its enormous mansions and famous residents