[FIX] hr_holidays: make approvals calendar working again

The fix introduced in #106513 was not working in the calendar found in
the "Approvals" menu as it was trying to call a model that was only
defined in the override of the CalendarModel that this view was not
inheriting.

closes odoo/odoo#108890

Signed-off-by: Kevin Baptiste <kba@odoo.com>

addons/hr_holidays/static/src/js/time_off_calendar.js

@@ -295,6 +295,7 @@ odoo.define('hr_holidays.dashboard.view_custo', function(require) {
         config: _.extend({}, CalendarView.prototype.config, {
             Controller: TimeOffCalendarController,
             Renderer: TimeOffPopoverRenderer,
+            Model: TimeOffCalendarModel,
         }),
     });