By Zoe Delaney Ryan Gosling and Eva Mendes continued to keep their romance low-key on Sunday night, as the Barbie actor attended the Oscars with his sister as his date. Eva, who shares two daughters with the Ken actor, excited fans earlier in the day, as the mum-of-two suggested she was ready to appear on the red carpet with her husband for the 96th Academy Awards, following years of the Hollywood couple keeping their relationship very private. Posting to Instagram in the afternoon, The Place Beyond The Pines actress, 50, shared a video of herself hanging out in Ryan’s Oscars dressing room bac…