[FIX] website: adapt offcanvas menu height on mobile

Prior to this commit, on mobile, we couldn't see the entire offcanvas
menu because the browser's UI was hidding part of it.

To fix that, this commit adapts the height of the offcanvas menu using
`dvh` unit.

task-3582657

closes odoo/odoo#141032

Signed-off-by: Romain Derie (rde) <rde@odoo.com>

addons/website/static/src/scss/website.scss

@@ -362,6 +362,8 @@ $-seen-urls: ();
     $-menu-color: o-color('menu-custom') or o-color('menu');
 
     @include o-bg-color($-menu-color);
+
+    height: 100dvh;
 }
 
 $-header-nav-link-height: $nav-link-height;

addons/website/views/website_templates.xml

@@ -322,7 +322,7 @@
                     </button>
                 </li>
             </ul>
-            <div t-attf-class="offcanvas #{_side if _side else 'offcanvas-end'} o_navbar_mobile vh-100" id="top_menu_collapse_mobile">
+            <div t-attf-class="offcanvas #{_side if _side else 'offcanvas-end'} o_navbar_mobile" id="top_menu_collapse_mobile">
                 <div class="offcanvas-header justify-content-end o_not_editable">
                     <button type="button" class="nav-link btn-close" data-bs-dismiss="offcanvas" aria-label="Close"/>
                 </div>
@@ -532,7 +532,7 @@
                         <t t-set="_dropdown_menu_class" t-valuef="dropdown-menu-end"/>
                     </t>
                 </ul>
-                <div class="offcanvas offcanvas-start o_navbar_mobile vh-100" id="top_menu_collapse">
+                <div class="offcanvas offcanvas-start o_navbar_mobile" id="top_menu_collapse">
                     <div class="offcanvas-header justify-content-end">
                         <button type="button" class="btn-close" data-bs-dismiss="offcanvas" aria-label="Close"/>
                     </div>