[CI] Remove unused imports with Ruff to pre-commit config, only to benchmarks/docs/examples folder (#3969)

benchmark/multi_turn_chat/long_prompt_multi_turn.py

@@ -1,13 +1,8 @@
-import itertools
 import json
-import os
 import random
-import string
-import threading
 import time
 from argparse import ArgumentParser
 from pathlib import Path
-from typing import Union
 
 from tqdm import tqdm