Account Fiscal Position Autodetect optional VIES

This module extends fiscal positions in Accounting with an extra condition based on VAT validation through VIES.

On the fiscal position form, a new checkbox "Vat was VIES validated" appears right after the existing "VAT required" option, and it is only visible when VAT is required. When enabled, the fiscal position is only considered for partners whose commercial entity has a VAT number that passed VIES validation.

When Odoo automatically looks for the right fiscal position for a customer or delivery address, it now takes the VIES validation status into account. Fiscal positions marked as requiring VIES validation are only selected for partners with a valid VIES status, while those not marked that way continue to work as before.

This affects the account.fiscal.position model and its automatic detection logic, so taxes and accounts applied on invoices and other accounting documents follow the correct fiscal position depending on the customer's VAT status. No new menus or reports are added; the change is visible in the fiscal position configuration screen and in the automatic fiscal position selection during document creation.