[FIX] l10n_it: Set English default for tax group subtotal labels

The Italian localization defined 'preceding_subtotal' in tax group records
using the Italian term "Imponibile" as the default value. This caused the
label for untaxed amounts in invoices, sale orders, and purchase orders
to always appear in Italian, regardless of the system or partner language.

Since this field is translatable, the correct approach is to define
the default in English (e.g., "Untaxed Amount") and provide Italian
translations via .po files.

This commit removes the hardcoded Italian values, enabling proper
language-sensitive display of tax totals.

task-4853046

closes odoo#213335

Signed-off-by: John Laterre (jol) <[email protected]>

Author: AhmedElemary57

addons/account/models/account_tax.py

@@ -46,6 +46,7 @@ class AccountTaxGroup(models.Model):
         string="Preceding Subtotal",
         help="If set, this value will be used on documents as the label of a subtotal excluding this tax group before displaying it. " \
              "If not set, the tax group will be displayed after the 'Untaxed amount' subtotal.",
+        translate=True,
     )
 
     @api.model

addons/l10n_it/data/account.tax.group.csv

@@ -1,12 +1,12 @@
 id,name,country_id/id,preceding_subtotal
-tax_group_iva_2,IVA 2%,base.it,Imponibile
-tax_group_iva_4,IVA 4%,base.it,Imponibile
-tax_group_iva_5,IVA 5%,base.it,Imponibile
-tax_group_iva_10,IVA 10%,base.it,Imponibile
-tax_group_iva_12,IVA 12%,base.it,Imponibile
-tax_group_iva_21,IVA 21%,base.it,Imponibile
-tax_group_iva_20,IVA 20%,base.it,Imponibile
-tax_group_iva_22,IVA 22%,base.it,Imponibile
-tax_group_imp_esc_art_15,Imponibile Escluso Art.15,base.it,Imponibile
-tax_group_fuori,Fuori Campo IVA,base.it,Imponibile
-tax_group_split_payment,Scissione dei Pagamenti,base.it,Scissione dei Pagamenti Esclusa
+tax_group_iva_2,IVA 2%,base.it,Taxable
+tax_group_iva_4,IVA 4%,base.it,Taxable
+tax_group_iva_5,IVA 5%,base.it,Taxable
+tax_group_iva_10,IVA 10%,base.it,Taxable
+tax_group_iva_12,IVA 12%,base.it,Taxable
+tax_group_iva_21,IVA 21%,base.it,Taxable
+tax_group_iva_20,IVA 20%,base.it,Taxable
+tax_group_iva_22,IVA 22%,base.it,Taxable
+tax_group_imp_esc_art_15,Imponibile Escluso Art.15,base.it,Taxable
+tax_group_fuori,Fuori Campo IVA,base.it,Taxable
+tax_group_split_payment,Scissione dei Pagamenti,base.it,Split Payments Excluded