Former President Donald Trump’s rally in Madison Square Garden kicked off a firestorm of controversy after a right-wing comic introducing him called Puerto Rico “a floating island of garbage,” with even hardcore MAGA Republicans immediately denouncing the joke as racist and inappropriate. But behind the scenes, the turmoil is even worse, CNN’s Kristen Holmes told Jake Tapper — even as on the surface of it, the Trump campaign considers the rally a rousing success. “Yesterday afternoon on ‘State of the Union,’ a bunch of Republican people that I had on the panel, commentators, said they hope tha…