Former President Barack Obama got a heads-up call from George Clooney that he was penning a bombshellopinion piece demanding President Joe Biden step down — and he didn’t try to stop it. Politico reported Clooney called Obama to warn him before the New York Times column was published Wednesday. Obama had been at the same Hollywood fundraiser where Clooney wrote he’d been shocked to see the president’s mental decline. He said he witnessed “the same man we all witnessed at the debate.” Want more breaking political news? Click for the latest headlines at Raw Story. Politico wrote that Obama made …