President Joe Biden is reportedly rehearsing his responses to “personally insulting” and “completely false” attacks by former President Donald Trump ahead of their crucial first debate of this year’s race for the White House. Veteran Democratic campaign lawyer Bob Bauer played the role of Trump during debate-prep sessions with Biden in 2020 and he’s believed by presidential aides to be doing so again as Biden gets ready for his Thursday face-off with Trump, Politico reported Saturday. Bauer, who also serves as Biden’s personal attorney, described the process in his new book, “The Unraveling: R…