No need for setting properties to default value
Use the localized format for the day
!fixup Internationalization.
Widget property values don't need i18n

It can actually lead to errors, as their values most probably would be
checked to literals with no internationalization.
Use the string directly as the i18n ID

No advantage for the translation, but it makes reading the code a bit
less easy. Also, for uniformity in the code, as the rest of the calls
to the MessageFactory are done without an ID.