[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>

vllm/entrypoints/openai/protocol.py

@@ -3,11 +3,11 @@
 # Adapted from
 # https://github.com/lm-sys/FastChat/blob/168ccc29d3f7edc50823016105c024fe2282732a/fastchat/protocol/openai_api_protocol.py
 import json
-import re
 import time
 from http import HTTPStatus
 from typing import Annotated, Any, ClassVar, Literal, Optional, Union
 
+import regex as re
 import torch
 from fastapi import HTTPException, UploadFile
 from pydantic import (BaseModel, ConfigDict, Field, TypeAdapter,