Sets or gets whether the time picker uses 12-hour or 24-hour format.
The useAmPmFormat only affects the display format. A time picker always
uses the 24-hour format for its value.
The useAmPmFormat property can be:
true: Displays a 12-hour time along with AM/PM indication. For example,
04:00 PM.false: Displays a 24-hour time. For example, 16:00.You can also set an element's useAmPmFormat property in the Editor using the Settings panel.