[FIX] hr_contract: Include archived employees on _get_all_contracts

Purpose
=======

When we want to retrieve all the contract (running for instance), we
don't care about the fact that the employee is archived or not.

For example when we generate the work entries to generate the payslips,
we actually pay the employee, even if he's archived (which is the
normal flow).

closes odoo/odoo#66836

X-original-commit: 262bf8598f9d885382c05e523543019767b521bf
Related: odoo/enterprise#16677
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>