before this commit, in the calendar view, if there is a field of selection field, instead of showing the filter value, currently it is shown as undefined. after this commit, the filter will show the selection value instead of undefined. closes odoo/odoo#118007 X-original-commit: edf838d791ee02f41af2bff32dc20b5657ef0d81 Signed-off-by: Bruno Boi (boi) <boi@odoo.com>