Include case: "fulltext_search" in SearchFilters.php

[psalido]

Next module replace SearchFilters.php from core with customized version including new query types.
However, current version of Next module forgets to consider new full search text query option. Thus, it'is not included among displayed filters.

In switch lack this case:

                    case 'fulltext_search':
                        $filterLabel = $translate('Search full-text');
                        $filters[$filterLabel][] = $value;
                        break;