[FIX] account_check_printing: manual payment method on payment widget

Steps to reproduce:

- On bank journal, set at least two manual
  outbound_payment_method_line_ids
- Set a vendor X with manual property_payment_method_id
- Create a Vendor Bill with vendor X, confirm it, and register payment
OR
- Create a payment with outbound method and select vendor X

Issue:

Got a traceback

The reason is we expected one value instead of several.

With this commit, we take the manual payment method with the
highest priority based on its sequence number.

opw-2743110

closes odoo/odoo#84643

Signed-off-by: William André (wan) <wan@odoo.com>