Last spring, I donned a sparkly disco dress and joined my college roommates in New York for “Summer: The Donna Summer Musical.” We were ready to dance the night away. But after the house dimmed all the lights, we dissolved in disappointment like cake in the rain as we sat through the painful pathos of the performer’s life, punctuated by fragments of her famous hits.On the screen, “Bohemian Rhapsody” is the opposite experience.It doesn’t really matter that this musical depiction of the …