[FIX] l10n_eg_edi_eta: division by zero during computation exchange rate

Steps to reproduce:
- Install modules: 'account_accountant', 'l10n_eg', 'l10n_eg_edi_eta'.
- Switch company to "EG Company".
- Configure "Large Cabinet Accounting" with ETA item code "10001138" and set Customer Taxes to "VAT 14%".
- In "Journal Customer Invoices", disable "Factur-X (FR)" under Advanced Settings -> Electronic invoicing. Also, set Branch to "Deco Addict", ETA Activity Code to "Accounting, auditing, bookkeeping and tax advice activities", and ETA Branch ID to 0.
- Update "Deco Addict" with Tax ID "204899053" and set building number to 2.
- Update "Azure Interior" with Tax ID "204899052" and set building number to 2.
- In Accounting -> Configuration -> Thumb Drive, create a new record using "EG Company" with 123 as both the ETA USB Pin and Access Token.
- Manually set the certificate in the Thumb Drive record.
- Create a new Customer Invoice with Customer set to "Azure Interior", Invoice Date as today, add a line item "Large Cabinet", set the Price to 0, remove "0% taxes" and add "VAT 14%", and set Journal to "Customer invoices in EUR".
- Confirm the invoice and attempt to "Sign Invoice".

Issue:
A traceback occurs with a divide by zero error in the invoice calculation when different currencies are involved.

Solution:
Refined _l10n_eg_edi_exchange_currency_rate function to calculate the currency exchange rate. Now, it ensures the division by amount_currency only occurs when it's not zero, preventing divide by zero errors during currency conversion in invoices.

opw-3580529

closes odoo/odoo#143064

X-original-commit: 14af8243188b86a0d654298feca6dc0980cbebeb
Signed-off-by: Florian Gilbert (flg) <flg@odoo.com>

addons/l10n_eg_edi_eta/models/account_move.py

@@ -5,6 +5,7 @@ import json
 
 from odoo import api, models, fields, _
 from odoo.exceptions import ValidationError, UserError
+from odoo.tools import float_is_zero
 from odoo.tools.sql import column_exists, create_column
 from datetime import datetime
 
@@ -121,4 +122,8 @@ class AccountMove(models.Model):
         self.ensure_one()
         from_currency = self.currency_id
         to_currency = self.company_id.currency_id
-        return abs(self.invoice_line_ids[0].balance / self.invoice_line_ids[0].amount_currency) if from_currency != to_currency and self.invoice_line_ids else 1.0
+        if from_currency != to_currency and self.invoice_line_ids:
+            amount_currency = self.invoice_line_ids[0].amount_currency
+            if not float_is_zero(amount_currency, precision_rounding=from_currency.rounding):
+                return abs(self.invoice_line_ids[0].balance / amount_currency)
+        return 1.0