feat(shared): add dynamic notifications link to navbar

The navbar now includes a functional link to the notifications dashboard instead of a placeholder.

**New Features**
- Added dynamic URL routing for the notifications link using Django's `{% url 'notifications_dashboard' %}` tag
```

templates/shared/navbar.html

@@ -82,7 +82,7 @@
                     </a>
                 </li>
                 <li>
-                    <a href="#"
+                    <a href="{% url 'notifications_dashboard' %}"
                         class="flex items-center py-2 px-3 text-heading rounded hover:bg-neutral-tertiary md:hover:bg-transparent md:hover:text-fg-brand md:p-0 md:dark:hover:bg-transparent transition-colors duration-200">
                         <svg class="w-5 h-5 me-2" aria-hidden="true" xmlns="http://www.w3.org/2000/svg" width="24"
                             height="24" fill="none" viewBox="0 0 24 24">