This commit fix a bug introduced in #66551 where a mismatch has been done between session.user_context.allowed_company_ids and session.user_companies.allowed_companies. This commit also adds the following tests: - a JS test in order to prevent future unwanted issues regarding multi company in BasicModel. - a Python test in order to ensure that session_info['user_companies'] is not involuntarily changed. closes odoo/odoo#68025 Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>