[FIX] l10n_in_edi_ewaybill: nil rated outside a state

Before this commit:
1.Create an Invoice in the demo company "E-Waybill Company" outside of the
  state (state other than set in the company)
2.Set the tax as nil rated and send e-way bill
E-Way Bill will not send.
Error message:
 [236]Tax rates for Inter state transaction is blank

After this commit:
E-Way Bill can be sent with nil rated tax for demo company 'E-Waybill Company'
outside of the state(state other than set in the company) 
task id:3304875

closes odoo/odoo#123616

X-original-commit: 2dc0bd3c7415e55c77c83f98e4c7088e0eaf82fc
Signed-off-by: Josse Colpaert <jco@odoo.com>

addons/l10n_in_edi_ewaybill/models/account_edi_format.py

@@ -477,8 +477,8 @@ class AccountEdiFormat(models.Model):
             "qtyUnit": line.product_id.uom_id.l10n_in_code and line.product_id.uom_id.l10n_in_code.split("-")[0] or "OTH",
             "taxableAmount": self._l10n_in_round_value(line.balance * sign),
         }
-        if tax_details_by_code.get("igst_rate"):
-            line_details.update({"igstRate": self._l10n_in_round_value(tax_details_by_code["igst_rate"])})
+        if tax_details_by_code.get("igst_rate") or (line.move_id.l10n_in_state_id.l10n_in_tin != line.company_id.state_id.l10n_in_tin):
+            line_details.update({"igstRate": self._l10n_in_round_value(tax_details_by_code.get("igst_rate", 0.00))})
         else:
             line_details.update({
                 "cgstRate": self._l10n_in_round_value(tax_details_by_code.get("cgst_rate", 0.00)),