[4.5] refactor: Filters by rector

[kenjis]

Description

1 file with changes
===================

1) system/Filters/Filters.php:620

    ---------- begin diff ----------
@@ @@
             }

             if (is_array($this->config->aliases[$alias])) {
-                $filtersClass = array_merge($filtersClass, $this->config->aliases[$alias]);
+                $filtersClass = [...$filtersClass, ...$this->config->aliases[$alias]];
             } else {
                 $filtersClass[] = $this->config->aliases[$alias];
             }
    ----------- end diff -----------

Applied rules:
 * LongArrayToShortArrayRector
 * ArraySpreadInsteadOfArrayMergeRector (https://wiki.php.net/rfc/spread_operator_for_array)

https://github.com/codeigniter4/CodeIgniter4/actions/runs/6601535164/job/17932652976

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide