test_leave_whole_company_07 test was failing due ot the hr_leave_date_check2
constraint.
This constraint check that date_from <= date_to for a leave.

date_from and date_to were not assigned any value before and had a default value
of fields.Datetime.now. Depending on which date_from or date_to is created first,
a few second difference can exist and this violates the hr_leave_date_check2 constraint

task-2726143

closes odoo/odoo#82131

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