Conservative attorney George Conway had a warning message for former President Donald Trump on MSNBC Friday: don’t pin all your hopes in the Manhattan criminal hush money trial on discrediting your former attorney and fixer Michael Cohen. Cohen, who has said he helped broker the payments to adult film star Stormy Daniels, has some drawbacks as a witness — in particular, Trump’s defense plans to capitalize on the fact that he pleaded guilty to lying to Congress — but there are some key reasons that may backfire, said Conway. “I think that Trump defense and the Trump campaign and Donald Trump ar…