撤回接口优化

app/enterprise/controller/Im.php

@@ -462,7 +462,7 @@ class Im extends BaseController
             $fromUserName = lang('im.other');
             $toContactId = $message['to_user'];
             if ($message['is_group'] == 1) {
-                $fromUserName = $this->userInfo['realname'];
+                $fromUserName = User::where('user_id',$message['from_user'])->value('realname');
                 $toContactId = explode('-', $message['chat_identify'])[1];
                 // 如果是群聊消息撤回，需要判断是否是群主或者管理员，如果是则可以撤回
                 if($message['from_user']!=$this->userInfo['user_id']){