[FIX] DateFormat: Make date input field use Gregorian date
[FIX] DateFormat: Make date input field use Gregorian date

On the DateFormat sample page, the input for datetime values now always uses Gregorian calendar, regardless of the calendar type chosen in the application.

Change-Id: I8de9275762e20f427ee5a87d53d0a98af28e3670

SAP/openui5,SAP/openui5,SAP/openui5,SAP/openui5