[TIMOB-17200] Fixed a bunch of bugs with Date and Time based Picker on M...

...obile Web. Turned off the border on the date/time input field since we already had one. Fixed change event so that it actually fires when the value changes and only when the value is a valid date object. Fixed the 'source' of the change event to be the actual Picker object. Fixed bug where widget-id was displaying as undefined.