[lint] tiny fix unimported packages. (#12927)

python/sglang/utils.py

@@ -13,11 +13,13 @@ import time
 import traceback
 import urllib.request
 import weakref
+from concurrent.futures import ThreadPoolExecutor
 from functools import wraps
 from io import BytesIO
 from json import dumps
 from typing import Any, Callable, List, Optional, Tuple, Type, Union
 
+import numpy as np
 import pybase64
 import requests
 from IPython.display import HTML, display