Jennifer Maas TV Business WriterAfter months of criticism and anticipation, “The Masked Singer” episode featuring the unmasking of Rudy Giuliani finally aired Wednesday on Fox. The show’s installment with the disgraced former mayor of New York City and former personal attorney for President Donald Trump, got a 0.6 demo rating and 3.6 million total viewers, according to fast-affiliate Nielsen data.Viewership for Season 7 has been in flux since its March 9 premiere, with the Fox celebrity singing competition drawing a season high 4.3 million viewers on March 30, only to reach a season low of 3.9 million last Wednesday — which was beat by last night’s new low.