Demo for managing 12-hour time

[hilibari]

This is a fantastic contribution to the community. Thanks for the sharing this.

It would be great if there was a clear path on how to accept 12-hour time. There is clearly some functionality for deal with 12-hour time baked into time-picker-utils.tsx. However, the implementation path is not super clear or defined. For instance, I can clearly there is a isValid12Hour function, which isn't being used.

It would be awesome to have an opinionated approach on how to manage 12-hour time!