[FIX] website_sale: fix open_website_url for product

open_website_url was targeting product_template website_url instead of
product_product.

Related to https://github.com/odoo/odoo/pull/33175

closes odoo/odoo#34383

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/website_sale/models/product.py

@@ -448,6 +448,13 @@ class Product(models.Model):
             res['url'] = self.website_url
         return res
 
+    @api.multi
+    def open_website_url(self):
+        self.ensure_one()
+        res = self.product_tmpl_id.open_website_url()
+        res['url'] = self.website_url
+        return res
+
     @api.multi
     def _get_images(self):
         """Return a list of records implementing `image.mixin` to