[IMP] website_sale: add an option to always show cart

Before this commit the cart was hidden when it was empty. Now we have
added a new option to display it any time.

Part of https://github.com/odoo/odoo/pull/49142
task-2229551

addons/website_sale/views/snippets.xml

@@ -95,6 +95,14 @@
                 <we-button data-change-sequence="bottom">Push to bottom</we-button>
             </div>
         </div>
+        <div data-selector="#wrapwrap > header"
+            data-no-check="true"
+            groups="website.group_website_designer">
+            <we-checkbox string="Always Show Cart"
+                        data-customize-website-views="website_sale.hide_cart_if_empty|"
+                        data-no-preview="true"
+                        data-reload="/"/>
+        </div>
     </xpath>
 </template>
 

addons/website_sale/views/templates.xml

@@ -75,8 +75,9 @@
     <template id="header" inherit_id="website.layout" name="Header Shop My Cart Link">
         <xpath expr="//header//ul[@id='top_menu']/li" position="before">
             <t t-set="website_sale_order" t-value="website.sale_get_order()" />
+            <t t-set="show_cart" t-value="true"/>
             <li class="nav-item divider d-none"/> <!-- Make sure the cart and related menus are not folded (see autohideMenu) -->
-            <li t-attf-class="nav-item o_wsale_my_cart #{'' if website_sale_order and website_sale_order.cart_quantity else 'd-none'}">
+            <li t-attf-class="nav-item o_wsale_my_cart #{not show_cart and 'd-none'}">
                 <a href="/shop/cart" class="nav-link">
                     <i class="fa fa-shopping-cart"></i>
                     My Cart <sup t-attf-class="my_cart_quantity badge badge-primary" t-esc="website_sale_order and website_sale_order.cart_quantity or ''" t-att-data-order-id="website_sale_order and website_sale_order.id or ''"/>
@@ -85,6 +86,12 @@
         </xpath>
     </template>
 
+    <template id="hide_cart_if_empty" inherit_id="website_sale.header" name="Hide Cart If Empty">
+        <xpath expr="//t[@t-set='show_cart']" position="after">
+            <t t-set="show_cart" t-value="show_cart and website_sale_order and website_sale_order.cart_quantity" />
+        </xpath>
+    </template>
+
     <!-- Products Search Bar input-group template -->
     <template id="website_sale_products_search_box" inherit_id="website.website_search_box" primary="True">
         <xpath expr="//input[@name='search']" position="attributes">