NEW YORK It may be hard to conceive of now, but there was once a lull in Mariah Carey’s superstar career. In 2001, her film “Glitter” was a commercial flop; the album that followed, 2002’s introspective “Charmbracelet,” was met with a muted response. She was at a crossroads. And then everything changed. Carey released “The Emancipation of Mimi” in 2005. It joined her athletic R&B-pop with synth-y hip-hop and fun, flirty, enduring hits — she was now only belting when she wanted to, thank you