[FIX] website_sale{,_stock}: fix issue with tests

Multiple tests introduced in 16.0 created a product template and then a
default product for that template, however a default product is already
created by default in the product module when creating a template and it
somecases triggered an unicity constraint.

closes odoo/odoo#108523

X-original-commit: 3c9ff6e148cd0ee77442dd31079f0fec9c456b4c
Related: odoo/enterprise#35180
Signed-off-by: William Braeckman (wbr) <wbr@odoo.com>

addons/website_sale/tests/test_website_sale_cart_abandoned.py

@@ -198,11 +198,7 @@ class TestWebsiteSaleCartAbandoned(TestWebsiteSaleCartAbandonedCommon):
             'list_price': 0.0,
             'name': 'free_product'
         })
-        free_product_product = self.env['product.product'].create({
-            'list_price': 0.0,
-            'name': 'free_product',
-            'product_tmpl_id': free_product_template.id
-        })
+        free_product_product = free_product_template.product_variant_id
         order_line = [[0, 0, {
             'name': 'The Product',
             'product_id': free_product_product.id,

addons/website_sale_stock/tests/test_website_sale_stock_abandoned_cart_email.py

@@ -20,10 +20,7 @@ class TestWebsiteSaleStockAbandonedCartEmail(TestWebsiteSaleCartAbandonedCommon)
             'type': 'product',
             'allow_out_of_stock_order': False
         })
-        storable_product_product = self.env['product.product'].create({
-            'name': 'storable_product_product',
-            'product_tmpl_id': storable_product_template.id,
-        })
+        storable_product_product = storable_product_template.product_variant_id
         order_line = [[0, 0, {
             'name': 'The Product',
             'product_id': storable_product_product.id,