refactor: reduce_multiples()

To suppress PHPStan false positive error.

Author: kenjis

system/Helpers/text_helper.php

@@ -526,7 +526,8 @@ function reduce_double_slashes(string $str): string
      */
     function reduce_multiples(string $str, string $character = ',', bool $trim = false): string
     {
-        $str = preg_replace('#' . preg_quote($character, '#') . '{2,}#', $character, $str);
+        $pattern = '#' . preg_quote($character, '#') . '{2,}#';
+        $str     = preg_replace($pattern, $character, $str);
 
         return ($trim) ? trim($str, $character) : $str;
     }