[IMP] base: have user_admin / partner_admin available in HttpCaseWithUserDemo on self
[IMP] base: have user_admin / partner_admin available in HttpCaseWithUserDemo on self

Purpose is to simplify future tests to have admin data directly available at
hand, both its user and partner. It will ease future test writing.

LINKS

Task ID 2290016 (improve visitor synchronization and tests)
Prepares Task ID 2252655 (main Online Event task)
Prepares Task ID 2284043 (Visitor-based track wishlist)
PR #54036

X-original-commit: f51fd6e54da5ee8aee0df74e6d510dc0b077eba8
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo