Comedian and political commentator Bill Maher mocked President Joe Biden Friday over his agreement to debate former President Donald Trump, saying that viewers will be watching for “proof of life” in the current president. Trump and Biden agreed Wednesday to participate in two televised debates: June 27 on CNN and Sept. 10 on ABC News. Maher said on his “Real Time” show Friday that Biden is the one with “more to prove.” “Trump is a known commodity,” Maher said. “They know he’s going to be an asshole. He’s going to be barking, and growling, and not obeying the rules and everything else.” Read: …