Use correct threshold for display of Change status list+button

Fix for issue #15258 introduced a check for 'update_bug_threshold' to
prevent unauthorized users from changing issue status.

This was not the correct config setting to use, the right one is
'update_bug_status_threshold'.

Fixes #16376

core/html_api.php

@@ -1395,8 +1395,8 @@ function html_button_bug_update( $p_bug_id ) {
 function html_button_bug_change_status( $p_bug ) {
 	$t_current_access = access_get_project_level( $p_bug->project_id );
 
-	# User must have updater access to use the change status button
-	if( !access_has_bug_level( config_get( 'update_bug_threshold' ), $p_bug->id ) ) {
+	# User must have rights to change status to use this button
+	if( !access_has_bug_level( config_get( 'update_bug_status_threshold' ), $p_bug->id ) ) {
 		return;
 	}