[Test] Remove VLLM_USE_V1 in example and tests (#1733)

V1 is enabled by default, no need to set it by hand now. This PR remove
the useless setting in example and tests

- vLLM version: v0.9.2
- vLLM main:
9ad0a4588b

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

examples/offline_inference_sleep_mode_npu.py

@@ -22,7 +22,6 @@ import torch
 from vllm import LLM, SamplingParams
 from vllm.utils import GiB_bytes
 
-os.environ["VLLM_USE_V1"] = "1"
 os.environ["VLLM_USE_MODELSCOPE"] = "True"
 os.environ["VLLM_WORKER_MULTIPROC_METHOD"] = "spawn"