Resolve locale not update issues in the chart view

- read locale from configuration rather than Locale.getDefault
- refine 12-24 format to align the current status bar short style
- resolve locale change not update chart percentage label
- extend timestamp label in the chart graph from 4 to 5 labels

Bug: 190150515
Bug: 190422902
Bug: 190226837
Test: make SettingsRoboTests
Change-Id: I5347964900123a6d112dbc37c2af87eb7d73f1d2