The real-life subject of Sydney Sweeney ’s new movie is speaking out on the “Euphoria” actor’s behalf following criticism of her performance. On Wednesday, former professional boxer Christy Martin shared a photo of her and Sweeney on the set of “Christy,” which hit theaters last week. “I’ve always been a fighter. My life reflected that in every way and now I fight for others,” Martin wrote in the caption. “The past few days I have seen some people attack my friend Sydney Sweeney. Syd not only