[FIX] web: blocked pop-up warning always shows

partial revert of https://github.com/odoo/odoo/pull/117205



Since there was no link between the odoo instance and the new tab,
it was impossible to determine if it was really open and the test
afterward would always trigger

closes odoo/odoo#117877

Signed-off-by: Vranckx Florian (flvr) <flvr@odoo.com>