Incorporate history icon link to slim_header.html template

wagtail/admin/templates/wagtailadmin/shared/headers/slim_header.html

@@ -22,6 +22,9 @@
                 {% if side_panels %}
                     {% include "wagtailadmin/shared/side_panel_toggles.html" %}
                 {% endif %}
+                {% if history_url %}
+                    {% include "wagtailadmin/shared/headers/_history_icon_link.html" with history_url=history_url nav_icon_button_classes=nav_icon_button_classes nav_icon_classes=nav_icon_classes only %}
+                {% endif %}
             {% endblock %}
         </div>
     </header>