[FIX] l10n_vn_edi_viettel: no need buyer district, correct buyercity

* Problem: Since what has been described in
odoo#214134 and
https://thuvienphapluat.vn/chinh-sach-phap-luat-moi/vn/ho-tro-phap-luat/chinh-sach-moi/82581/tu-ngay-01-7-2025-ca-nuoc-se-khong-con-quan-huyen
Vietnam no longer have district and city in city no more (Before in
Vietnam we will have Thu Duc City belong to Ho Chi Minh State or Thuy
Nguyen City belong to Hai Phong), Therefore we need to update Sinvoice
data for this to.

* This commit remove BuyerDistrict parameter , beside using state in the
district is totally wrong and for 'buyerCityName' accept city or state
field because odoo user might leave the city empty and just input state

closes odoo#219368

X-original-commit: d4f424d
Signed-off-by: Nicolas Viseur (vin) <vin@odoo.com>

Author: daiduongnguyen-odoo

addons/l10n_vn_edi_viettel/models/account_move.py

@@ -628,8 +628,7 @@ def _l10n_vn_edi_add_buyer_information(self, json_values):
             'buyerAddressLine': self.partner_id.street,
             'buyerPhoneNumber': commercial_partner_phone or '',
             'buyerEmail': self.commercial_partner_id.email or '',
-            'buyerDistrictName': self.partner_id.state_id.name,
-            'buyerCityName': self.partner_id.city,
+            'buyerCityName': self.partner_id.city or self.partner_id.state_id.name,
             'buyerCountryCode': self.partner_id.country_id.code,
             'buyerNotGetInvoice': 0,  # Set to 1 to no send the invoice to the buyer.
         }

addons/l10n_vn_edi_viettel/tests/test_edi.py

@@ -38,7 +38,7 @@ def setUpClass(cls):
         cls.partner_a.write({
             'street': '121 Hang Bac Street',
             'state_id': cls.env.ref('base.state_vn_VN-HN').id,
-            'city': 'Hoan Kiem District',
+            'city': 'Hà Nội',
             'country_id': cls.env.ref('base.vn').id,
             'vat': '0100109106-505',
             'phone': '3825 7670',
@@ -116,8 +116,7 @@ def test_json_data_generation(self):
                     'buyerAddressLine': '121 Hang Bac Street',
                     'buyerPhoneNumber': '38257670',
                     'buyerEmail': 'partner_a@gmail.com',
-                    'buyerDistrictName': 'Hà Nội',
-                    'buyerCityName': 'Hoan Kiem District',
+                    'buyerCityName': 'Hà Nội',
                     'buyerCountryCode': 'VN',
                     'buyerNotGetInvoice': 0,
                 },