Define default $g_set_status_threshold for NEW to REPORTER

This prevents incorrect highlighting of NEW status as an override in the
Access Levels section of manage_config_workflow_page.php, when
$g_bug_submit_status is different from default.

Fixes #14496 (see atrol's bugnote ~33192 and my follow up in ~33325)

config_defaults_inc.php

@@ -2826,7 +2826,7 @@
  * );
  * @global array $g_set_status_threshold
  */
-$g_set_status_threshold = array();
+$g_set_status_threshold = array( NEW_ => REPORTER );
 
 /**
  * Threshold at which a user can edit his/her own bugnotes.