Default Time Display Format for China Region Should be 24 Hour

The default time display format for China region should be 24 hour.

According to China's current national standards (GB/T 7408-2005 (sorry for only Chinese version available), which is equivalent to the ISO international standard: ISO 8601:2000 and ISO 8601:2004, titled Data elements and interchange formats — Information interchange — Representation of dates and times), local time should be based upon the 24-hour timekeeping system. New ISO standard ISO 8601-1:2019, revised ISO 8601:2004, also says "times based on the 24-hour clock", this standard is also a recommended standard in China.

The actual affected version includes all released versions of Qt 5 and Qt 6.