Remove copyright header from hellaswag_utils.py

eval/open_llm_leaderboard/hellaswag_utils.py

@@ -1,6 +1,3 @@
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-# This software may be used and distributed according to the terms of the Llama 2 Community License Agreement.
-
 import datasets
 import re