District Attorney Fani Willis and a top lieutenant in the Georgia racketeering case against former President Donald Trump Thursday both admitted on the witness stand that they had a sexual affair but denied any impropriety that could impact the case. In a dramatic courtroom moment, Willis rose and told the court that she would take the stand: “I’m ready to go.” The Atlanta prosecutor angrily rebutted salacious claims that her affair with prosecutor Nathan Wade amounted to an impermissible conflict of interest in the explosive case against Trump for allegedly seeking to steal the presidential e…