fix: corrected issue with invalid date values

Author: thorsten

phpmyfaq/assets/templates/admin/configuration/upgrade.twig

@@ -153,7 +153,11 @@
     </div>
     <div>
       {{ 'msgLastCheckDate' | translate }}
-      {% set lastCheck = dateLastChecked == 'Invalid Date' ? 'n/a' : dateLastChecked | date('Y-m-d H:i:s') %}
+      {% if dateLastChecked == 'Invalid Date' %}
+        {% set lastCheck = 'n/a' %}
+      {% else %}
+        {% set lastCheck = dateLastChecked | date('Y-m-d H:i:s') %}
+      {% endif %}
       <output id="dateLastChecked">{{ lastCheck }}</output>
     </div>
     <div>