If a partner has no VAT number (for instance: a public administration), the xml tag `PartyTaxScheme` should not appear for UBL Bis 3. opw-3263542 closes odoo/odoo#119261 X-original-commit: 270ed9f92ee9c71cc38c4cc69fb2d7c2c780cf52 Signed-off-by: Laurent Smet <las@odoo.com> Signed-off-by: Julien Van Roy <juvr@odoo.com>