chore(datax): plugin.py 删死 import pwd

grep 确认全文件无 pwd.* 使用，Windows 平台缺 pwd 模块导致 cli 单测
import 链阻塞，一行清理打通

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dw_base/datax/plugins/plugin.py

@@ -1,7 +1,6 @@
 # -*- coding:utf-8 -*-
 
 import os
-import pwd
 import re
 from configparser import ConfigParser
 from datetime import datetime