[FIX] event_sale: fix unit test

Steps to reproduce:

- Install any localization account module
- Install event_sale
- Run the unit test :TestEventSale.test_ticket_price_with_currency_conversion

Current behaviour:
The unit test will fail in line 341

Expected behaviour:
The unit test should not fail

Explanation:
The unit test used self.env.company which will populate demo invoices after installing
the localization account module. Therefore we can't change the currency on the company
any more in event_sale/tests/test_event_sale.py line 341. It is better to create a new
company in the unit test to prevent side effect like this.

closes odoo/odoo#117286

X-original-commit: 96998664285c00ab3d3ac6491123e596cfa9b3e8
Signed-off-by: William André (wan) <wan@odoo.com>

addons/event_sale/tests/test_event_sale.py

@@ -338,7 +338,14 @@ class TestEventSale(TestEventSaleCommon):
 
         currency_VEF = _prepare_currency(self, 'VEF')
         currency_USD = _prepare_currency(self, 'USD')
-        self.env.user.company_id.currency_id = currency_USD
+
+        company_test = self.env['res.company'].create({
+            'name': 'TestCompany',
+            'country_id': self.env.ref('base.be').id,
+            'currency_id': currency_USD.id,
+        })
+        self.env.user.company_ids += company_test
+        self.env.user.company_id = company_test
 
         pricelist_USD = self.env['product.pricelist'].create({
             'name': 'pricelist_USD',