Original PR description

A change from odoo/enterprise#116705 made the
`iot_http_service` try to access the `self_ordering_mode`
on the session`, leading to longpolling failure on non-self order
as data would be undefined.

Also, a mistake in error catching in the longpolling service
made it so that an event request thrown would abort directly
with the previous one, instead of only the previous one.

If websocket was unavailable at the same time, it would
result on the PoS getting stuck waiting for confirmation
of the payment.

In addition, we fixed Six payments in Kiosk, failing
because it tryed to access `user.id` where user was
`undefined`.

task-6391166

Forward-Port-Of: odoo/enterprise#124782