[FIX] base: Make OdooBot partner cross company

Steps to reproduce:
- Create a second company
- Enable this company only
- Create a new company
=> Access error is raised because the `intercompany_user_id` is
OdooBot by default and OdooBot's partner cannot be read from
other companies. Hence, the company creation fails.

Like all other internal users/partners, OdooBot's partner should
be shared across companies, even if its user is inactive.

Task 2157039

See also 2390ba60

Task 2157039

closes odoo/odoo#49926

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