[FIX] website_sale: product attribute line

In e-commerce, on a product page. If the product has some attributes
("product.attribute.line" model) with several values for at least one attribute
(which means several variants for one product), the display of these attributes must
respect the sequence defined in:
Sales > configuration > products > attributes("product.attribute" model)

opw:648634

addons/website_sale/views/templates.xml

@@ -415,7 +415,7 @@
 <template id="variants">
   <t t-set="attribute_value_ids" t-value="get_attribute_value_ids(product)"/>
   <ul t-attf-class="list-unstyled js_add_cart_variants #{ul_class}" t-att-data-attribute_value_ids="attribute_value_ids">
-    <t t-foreach="product.attribute_line_ids" t-as="variant_id">
+    <t t-foreach="product.attribute_line_ids.sorted(key=lambda x: x.attribute_id.sequence)" t-as="variant_id">
       <li t-if="len(variant_id.value_ids) > 1">
 
         <strong t-field="variant_id.attribute_id.name"/>