LAS VEGAS — For a 29th consecutive season, the trophy case in the 49ers’ Santa Clara lobby won’t need to expand for a long-awaited sixth Lombardi Trophy. The Kansas City Chiefs repeated as Super Bowl champions Sunday night by outlasting the 49ers 25-22 in a thrilling overtime game at Allegiant Stadium. Patrick Mahomes ruined the 49ers’ Super Bowl hopes for the second time in four years, this time saving his game-winning ways for a touchdown pass to Mecole Hardman with three seconds remaining in overtime. Hardman slipped past nickel back Logan Ryan to get wide open, and as he crossed the goal l…