ui: Fix link to the API when browsing tasks

It's intended that the API link changes based on the page.

The playbook list and host list links were fine but it seems we had
forgotten about the task list link.

ara/ui/templates/partials/api_link.html

@@ -9,6 +9,8 @@
  {% else %}
  <a href="{% url 'latesthost-list' %}" class="nav-link" target="_blank">API</a>
  {% endif %}
+{% elif page == "task_index" %}
+ <a href="{% url 'task-list' %}" class="nav-link" target="_blank">API</a>
 {% elif playbook.id %}
  <a href="{% url 'playbook-detail' pk=playbook.id %}" class="nav-link" target="_blank">API</a>
 {% elif result.id %}