[FIX] payment: user is able to delete linked journals

Steps to reproduce:

1- install any payment acquirer (e.g. stripe)
2- configure the payment acquirer and link it to a journal
3- try to delete the journal
4- the journal can be deleted which will create an internal server
error when this payment acquirer is used

Bug:

There is no restriction on deleting `account.journal` linked to
payment acquirers

Fix:

add a restriction that forces the user to remove the journal from the
payment acquirers first

OPW-3089006

closes odoo/odoo#107842

Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>