Toggle 24-hour and 12-hour Time input

[schnautz]

Is your feature request related to a problem? Please describe. When creating a date/time automation, it accepts 24-hr notation only. Through no fault but my own, I occasionally do the conversion incorrectly in my head.

If the interface allowed entry in 12-hour (AM/PM) format, I'd be less likely to make mistakes in the setup of my scripts.