[FIX] website_sale_options: Test not enough restrictive

The `shop_customize` test (`website_sale.test.js`) relies on
a link containing 'shop'.

The probability to have several links in the ecommerce containing
'Shop' is high, and we therefore specify a bit more the test
to prevent the test to fail if other modules (community/extra)
add links containing 'Shop' within the ecommerce

opw-640639

addons/website_sale_options/static/src/js/website_sale.test.js

@@ -71,7 +71,7 @@
             },
             {
                 title:     "click on shop",
-                element:   "a:contains(Shop)",
+                element:   "a:contains(Continue Shopping)",
                 waitNot:   '#products_grid_before .js_attributes',
             },
             {