Fix time selection on datetime widget in edit mode

When configuring the datetime widget to show the time (thanks to the pattern used) in edit mode, the calendar does not make it possible to select the date and the time at the same time because popup closes after chosing a date.
Solution is to use the property "showApplyButton" set to true, as the user will have to click on the "Apply" button to close the popup.

Problem is that this property does not resolve EL expressions correctly on the rich:calendar component, and widget configuration wraps properties in EL expressions to ensure usage of references (and fix some ajax re-render issues).

=> need to exclude that property from the wrapping.