By Jamie Roberts Ryan Gosling is ready to entertain at the biggest night of this year’s showbiz calendar. As the 96thAcademy Awards descends on Hollywood tonight, the 43-year-old Barbie star was said to be in “great spirits” ahead of his performance of I’m Just Ken. The tune was a huge success in the award-winning Barbie movie last year and the A-list actor is ready to wow onlookers with a live performance. It’s said he was looking fabulous during final rehearsals on Friday at the Dolby Theatre, where the Oscars will be held. For all the latest on news, politics, sports, and showbiz from the U…