The first image presented in the new Broadway musical “Tammy Faye,” before the curtain even rises, is a pair of gleaming, heavily mascaraed blue eyes, representing those of the show’s heroine, Tammy Faye Bakker. Then, as the orchestra begins to play, those eyes well up and leak tears, and that mascara — through a trick of Finn Ross’s video design — begins to streak, quickly forming sizable smudges.