Remove order_name from groupOrder emails export

This column was quite useless, since the export grouped order email addresses is
done for a given grouped order, so the value was the same throughout the CSV.

la_chariotte/order/views/grouped_order.py

@@ -345,9 +345,9 @@ class ExportGroupOrderEmailAdressesToDownloadView(UserPassesTestMixin, generic.V
             filename = f"commande _{grouped_order.name.replace(' ', '_')}"
             response["Content-Disposition"] = f'attachment; filename="{filename}.csv"'
             writer = csv.writer(response)
-            writer.writerow(["order_name", "email"])
+            writer.writerow(["email"])
             for email in email_list:
-                writer.writerow([grouped_order.name, email])
+                writer.writerow([email])
             return response
         else:
             email_list = ";\n".join(email_list)

la_chariotte/tests/test_order_views_grouped_order.py

@@ -1521,8 +1521,8 @@ class TestExportGroupOrderEmailAdressesToDownloadView:
         assert response.status_code == 200
         assert response["Content-Type"] == "text/csv"
         content = response.content.decode()
-        assert "order_name,email" in content
-        assert "order_name,email\r\ngr order test,test@mail.fr\r\n" in content
+        assert "email" in content
+        assert "email\r\ntest@mail.fr\r\n" in content
 
     def test_export_format_default(self, client_log):
         grouped_order = create_grouped_order(