configs: overwrite via prepend, mode instead of duration_only (#715)

templates/timesheet/index.html.twig

@@ -17,6 +17,7 @@
     {% if entries.count == 0 %}
         {{ widgets.callout('warning', 'error.no_entries_found') }}
     {% else %}
+        {% set duration_only = is_duration_only() %}
         {% set canSeeRate = is_granted('view_rate_own_timesheet') %}
         {% set columns = {'date': ''} %}