[FIX] hr_holidays: copy accrual fields when creating child allocations

Create an accrual leave, and set it e.g. by employee tag.
For each employee having the tag, a child allocation will be created.
When doing so, it will prepare the values for these creations.
However the relevant fields for accrual leaves were missing from these values.

opw 1906476

closes odoo/odoo#28492

addons/hr_holidays/models/hr_leave_allocation.py

@@ -374,6 +374,11 @@ class HolidaysAllocation(models.Model):
             'parent_id': self.id,
             'employee_id': employee.id,
             'accrual': self.accrual,
+            'date_to': self.date_to,
+            'interval_unit': self.interval_unit,
+            'interval_number': self.interval_number,
+            'number_per_interval': self.number_per_interval,
+            'unit_per_interval': self.unit_per_interval,
         }
         return values