Fix preserving query strings for error page redirects

Author: shivammathur

error.php

@@ -19,7 +19,8 @@
 // Get URI for this request, strip leading slash
 // See langchooser.inc for more info on STRIPPED_URI
 $URI = substr($_SERVER['STRIPPED_URI'], 1);
-$queryString = $_SERVER['QUERY_STRING'] ?? '';
+$uriParts = explode('?', $URI, 2);
+$queryString = isset($uriParts[1]) ? html_entity_decode($uriParts[1], ENT_QUOTES, 'UTF-8') : '';
 
 // ============================================================================
 // Mozilla Search Sidebar plugin resource file handling (need to be mirror