[FIX] website_sale: do not compute price of every pricelist

This controller was very slow as not providing a pricelist computed the price of
all products of all pricelists.
Instead only fetch the prices for the useful products.

addons/website_sale/controllers/main.py

@@ -972,7 +972,7 @@ def get_unit_price(self, product_ids, add_qty, use_order_pricelist=False, **kw):
             pricelist_id = request.session.get('sale_order_code_pricelist_id') or partner.property_product_pricelist.id
         else:
             pricelist_id = partner.property_product_pricelist.id
-        prices = pool['product.pricelist'].price_rule_get_multi(cr, uid, [], [(product, add_qty, partner) for product in products], context=context)
+        prices = pool['product.pricelist'].price_rule_get_multi(cr, uid, [pricelist_id], [(product, add_qty, partner) for product in products], context=context)
         return {product_id: prices[product_id][pricelist_id][0] for product_id in product_ids}
 
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