Improve X axis labels in battery chart (2)

Support showing different numbers of labels for different count of
trapezoids.

screen_record: https://drive.google.com/file/d/1CIgppQllHlKC3BGG7hBvOjGDGVOs6OYC/view?usp=sharing&resourcekey=0-mbofu5KOO2dqCwL7K0zakg

Test: manual
Bug: 239491373
Bug: 236101166
Change-Id: I865dae760b491bdd7c93bbd29fd7dbc33204a60a