[FIX] l10n_latam_check: Prevent Multiple Uses of Same Third-Party Check

there is a loophole that allows the same third-party check to be used
for multiple outbound payments. This issue causes data inconsistencies
and disrupts the expected behavior of the financial workflow, thereby
undermining the integrity of the accounting processes.

In order to address it a  constraint was introduced on the
l10n_latam_check_id field. This constraint is triggered whenever
a payment transaction involves the use of 'out_third_party_checks' as
the payment method. The system now conducts a search to identify any
pre-existing payments that might be using the same third-party check.
If a duplicate use of a check is detected, a ValidationError is promptly
raised, effectively blocking the transaction.

Task-3503556

closes odoo/odoo#135815

Signed-off-by: de Wouters de Bouchout Jean-Benoît (jbw) <jbw@odoo.com>