We hate to be the bearer of bad news for Lady Gaga. The singer said on Monday that she still loves ex-fiancé Taylor Kinney and joked she won’t be celebrating when he starts to date again. But Page Six is told that the “Chicago Fire” actor — who was engaged to Gaga for 18 months until their July split— has already moved on. Insiders say that Kinney has been quietly dating a 26-year-old girl from South Philadelphia, Alanna DiGiovanni, and unlike his ex’s alter ego, we’re told she’s not a