[FIX] sale: singleton error when validating payments
[FIX] sale: singleton error when validating payments

- When validating a payment an "expected singleton" exception is
raised due to the fact that we are using a recordset with multiple
record instead of a recordset with a single record.

OPW-1981632

closes odoo/odoo#33767

Signed-off-by: Christophe Simonis <0e117f2b429bfa19751522a564765b352cb7b946@odoo.com>
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo