Margot Robbie’s voiceover dominates the first half of Birds of Prey. As Harley Quinn, she’s the film’s oddly reliable narrator (here, as in the comics, she’s both a former psychiatrist and a freewheeling, gleefully deranged criminal), providing both a narrative on-ramp and a syrupy, did-I-do-bad running commentary that’s likely to be funny only to herself. […]