[FIX] hr_holidays: Fix smart-button display of remaining time off

This PR fixes the display of remaining days that wasn't correctly displayed when an allocation
had no time limit.
task-3414291

closes odoo/odoo#134584

X-original-commit: 5fc84bd71fca69862ef4eb3fbb956a18c951d8d0
Signed-off-by: Sofie Gvaladze (sgv) <sgv@odoo.com>
Signed-off-by: Jurgen Gjini (jugj) <jugj@odoo.com>

addons/hr_holidays/models/hr_employee.py

@@ -89,6 +89,8 @@ class HrEmployeeBase(models.AbstractModel):
             ('holiday_status_id.requires_allocation', '=', 'yes'),
             ('state', '=', 'validate'),
             ('date_from', '<=', current_date),
+            '|',
+            ('date_to', '=', False),
             ('date_to', '>=', current_date),
         ], ['employee_id'], ['__count', 'number_of_days:sum'])
         rg_results = {employee.id: (count, days) for employee, count, days in data}