Use function buildMonitorsFilters instead of using ob_get_contents (montage.php)

web/skins/classic/views/montage.php

@@ -181,10 +181,10 @@ if (!empty($_REQUEST['maxfps']) and validFloat($_REQUEST['maxfps']) and ($_REQUE
 
 session_write_close();
 
-ob_start();
 include('_monitor_filters.php');
-$filterbar = ob_get_contents();
-ob_end_clean();
+$resultMonitorFilters = buildMonitorsFilters();
+$filterbar = $resultMonitorFilters['filterBar'];
+$displayMonitors = $resultMonitorFilters['displayMonitors'];
 
 $need_hls = false;
 $need_janus = false;