Logging and minor fixes to two batch overlap and EPLB (#6595)

python/sglang/srt/utils.py

@@ -44,6 +44,7 @@ from functools import lru_cache
 from importlib.metadata import PackageNotFoundError, version
 from importlib.util import find_spec
 from io import BytesIO
+from json import JSONDecodeError
 from multiprocessing.reduction import ForkingPickler
 from pathlib import Path
 from typing import (