fix(agent): type of is_online is specific

if set to boolean, the light gree or red does not show

Signed-off-by: Thierry Bugier <tbugier@teclib.com>

inc/agent.class.php

@@ -820,7 +820,7 @@ public function getSearchOptionsNew() {
          'table'              => $this->getTable(),
          'field'              => 'is_online',
          'name'               => __('Is online', 'flyvemdm'),
-         'datatype'           => 'bool',
+         'datatype'           => 'specific',
          'massiveaction'      => false
       ];