Fix Spreadsheet: multiple users/groups mapping works only for users and prefix them although it should not

When using JSF UI, the use of spreadsheet to modify values of type user or group will result in the display of values prefixed with either "user:" or "group:", or warnings in edition if the widget to display the data has the property "use prefixed reference" set to "No". In the Studio project, it is now required to use the property "use prefixed reference" set to "Yes" in creation, view, edit screens and also in content views for the data of type "user" or "group" to enable the seamless usage of spreadsheet. Regarding preexisting data created with versions of the Studio project not having the widget property set to "Yes" for all data of type "user/group" and used in conjunction with spreadsheet, 4 cases arise: For USER ONLY type of data, ensure the data in database is prefixed with "user:" For GROUP ONLY type of data, ensure the data in database is prefixed with "group:" For a MIX of users and groups, the default value in Studio for the property is "Yes": if having not changed this default in Studio, no action to take in this case For a MIX of users and groups, you changed the default value of the property to "No": edit the values in database to prefix with either "user:" or "group:" depending on the type of value.