Убрать слешь в json

     public function deleteUnicode($mixed) { функция распознавания кирилиццы 
      return preg_replace_callback(
        "/\\\\u([a-f0-9]{4})/",
        function($matches) {
            return iconv('UCS-4LE','UTF-8',pack('V', hexdec('U' . 
    $matches[0])));
        },
        json_encode($mixed)
    );
 }


 public function handle(Request $request, Closure $next)
{
    $response = $next($request);
    $logs = [
        'IP' => $request->ip(),
        'URI' => $request->getUri(),
        'REQUEST_BODY' => $request->all(),
        'PARTNER_ID' => $request->partner_id,
        'RESPONSE' => $response->getContent(),
    ];

    Log::create([
        'ip' => $logs['IP'],
        'url' => $logs['URI'],
        'partner_id' => $logs['PARTNER_ID'],
        'request' => json_encode($logs['REQUEST_BODY']),
        'response' => $this->deleteUnicode($logs['RESPONSE'])
    ]);

    return $response;
}

'response' => $logs['RESPONSE'] возвращает json, вот в таком виде:

"{"error":"\С\у\м\м\а \с\т\р\а\х\о\в\к\и \н\е \м\о\ж\е\т \п\р\е\в\ы\ш\а\т\ь 2 \м\и\л\л\и\о\н\а","code":422}"

как убрать слешь везде?