[Bugfix] Migrate to REGEX Library to prevent catastrophic backtracking (#18454)

Signed-off-by: Crucifixion-Fxl <xmufxl@gmail.com>
Co-authored-by: Crucifixion-Fxl <xmufxl@gmail.com>

tests/v1/entrypoints/openai/test_completion.py

@@ -1,11 +1,11 @@
 # SPDX-License-Identifier: Apache-2.0
 
-import re
 from typing import Optional
 
 import openai  # use the official client for correctness check
 import pytest
 import pytest_asyncio
+import regex as re
 from openai import BadRequestError
 
 from tests.utils import RemoteOpenAIServer