[IMP] web: reintroduce the border for last kanban example page

This is cleaner and allows a more obvious line between the page
and the contents, especially since there will be a weird spacing
below the last element of the page list. This styling (vertical
notebook) is only used for the kanban example dialog and has a
limited impact.

The border was removed in the following commit:
16ddf96

task-3113972

closes odoo#109105

Related: odoo/enterprise#35438
Signed-off-by: Warnon Aurélien (awa) <awa@odoo.com>

addons/web/static/src/core/notebook/notebook.scss

@@ -60,10 +60,6 @@
             &:first-child .nav-link {
                 border-top-width: 0;
             }
-
-            &:last-child .nav-link {
-                border-bottom-width: 0;
-            }
         }
 
         .nav-link {