[FIX] hr_holidays: fix multi company issue in days calculation

Prior to this commit, the multi company rules were bypassed due implicit
sudos (compute_sudo and self.env.user).
The function computing the number of days will now make sure to include
the right domain.

TaskId-2791030

closes odoo/odoo#86166

Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>