Fixes #12961: Set correct return_url for object contacts tabs

netbox/templates/tenancy/object_contacts.html

@@ -2,10 +2,12 @@
 {% load helpers %}
 
 {% block extra_controls %}
-    {% if perms.tenancy.add_contactassignment %}
-    <a href="{% url 'tenancy:contactassignment_add' %}?content_type={{ object|content_type_id }}&object_id={{ object.pk }}&return_url={{ object.get_absolute_url }}" class="btn btn-primary btn-sm">
+  {% if perms.tenancy.add_contactassignment %}
+    {% with viewname=object|viewname:"contacts" %}
+      <a href="{% url 'tenancy:contactassignment_add' %}?content_type={{ object|content_type_id }}&object_id={{ object.pk }}&return_url={% url viewname pk=object.pk %}" class="btn btn-primary btn-sm">
         <i class="mdi mdi-plus-thick" aria-hidden="true"></i> Add a contact
-    </a>
+      </a>
+    {% endwith %}
   {% endif %}
 {% endblock %}