Fixed formatting of hidden filters.

- This was likely broken by formatting logic introduced by hidden filter persistence logic.

module/VuFind/src/VuFind/Recommend/AuthorityRecommend.php

@@ -117,7 +117,7 @@ class AuthorityRecommend implements RecommendInterface
                 if ($params[$i] == '__resultlimit__') {
                     $this->resultLimit = intval($params[$i + 1]);
                 } else {
-                    $this->filters[] = $params[$i] . ':(' . $params[$i + 1] . ')';
+                    $this->filters[] = $params[$i] . ':' . $params[$i + 1];
                 }
             }
         }