“Charlotte,” the animated retelling of the true-life, World War II-era story of German-Jewish artist Charlotte Salomon, is more of a middling proposition than one might expect from this singular tale. Salomon was yet another in the endless line of notable and compelling figures whose lives were shaped — and devastated — by the Holocaust. But the film, although lovingly made, often feels too rudimentarily written and rendered to be sufficiently impactful. (Dutch filmmaker Frans Weisz made both a 1981 live-action biopic and a 2012 documentary about Salomon, though they were not widely seen in the U.S.) Directed by Tahir Rana...