[minor] simplify the TokenToKVPoolAllocator (#7414)

python/sglang/srt/managers/scheduler.py

@@ -23,7 +23,6 @@ import time
 from collections import defaultdict, deque
 from concurrent import futures
 from dataclasses import dataclass
-from http import HTTPStatus
 from pathlib import Path
 from types import SimpleNamespace
 from typing import Dict, List, Optional, Tuple, Union