[FIX] hr_holidays: Leaves in Multi companies

Steps to reproduce the bug:

- Let's consider 3 companies C1, C2, C3 where C1 and C2 are childs of C3
- Let's consider 3 employees E1, E2, E3 respectively in C1, C2, C3
- Create a user U with administrator access rights in Leaves and U is linked to E3
- Log as U in C3
- Create a Leave Type LT with no company
- Create a leave LT  LT1 for E1 and LT2 for E2
- Change your current company to C2
- Click on LT1

Bug:

An access right error was raised

opw:2431572

closes odoo/odoo#65068

Signed-off-by: Simon Goffin (sig) <sig@openerp.com>