[FIX] website: add missing role in parent elements on submenu

Currently, <ul> and <li> is missing `role` in navbar. This thing can
effect on accessibility point on Lighthouse report.
https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/menuitem_role

This PR will fix this problem

closes odoo/odoo#137790

X-original-commit: 21ce76703a9b1496e6824be7aa19946c37cca37c
Signed-off-by: Romain Derie (rde) <rde@odoo.com>

addons/website/views/website_templates.xml

@@ -3,7 +3,7 @@
 
 <template id="submenu" name="Submenu">
     <t t-set="show_dropdown" t-value="(submenu.is_mega_menu and submenu.is_visible) or submenu.child_id.filtered(lambda menu: menu.is_visible)"/>
-    <li t-if="submenu.is_visible and not (submenu.child_id or submenu.is_mega_menu)" t-attf-class="#{item_class or ''}">
+    <li t-if="submenu.is_visible and not (submenu.child_id or submenu.is_mega_menu)" t-attf-class="#{item_class or ''}" role="presentation">
         <a t-att-href="submenu._clean_url()"
             t-attf-class="#{link_class or ''} #{submenu._is_active() and 'active'}"
             role="menuitem"
@@ -276,7 +276,7 @@
 </template>
 
 <template id="navbar_nav" name="Navbar Nav">
-    <ul id="top_menu" t-attf-class="nav navbar-nav o_menu_loading #{_nav_class}">
+    <ul id="top_menu" t-attf-class="nav navbar-nav o_menu_loading #{_nav_class}" role="menu">
         <t t-out="0"/>
     </ul>
 </template>