This implements an explicit toggle to enable/disable automatic 12h/24h time formatting detection based on the current locale. Previously automatic detection was the norm on a freshly wiped device, but could never be re-enabled once either 12h or 24h format was configured. Bug: 32761619 Test: m RunSettingsRoboTests Change-Id: Idbbb8f79fccec95e33bf2f12767d5736e1118fa7