[FIX] point_of_sale: avoid trouble when no chart template installed

When a session is created and no orders can be created because of
misconfiguration. We should be able to close the session.

When a chart of account is installed, we should not try to create
payment methods on config that have active session as it is forbidden.

Check that there is at least one payment method configured when
launching a session.

closes odoo/odoo#61933

Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>