[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>

tests/e2e/multicard/test_ilama_lora_tp2.py

@@ -1,7 +1,7 @@
 import pytest
 from modelscope import snapshot_download  # type: ignore
 
-from tests.conftest import VllmRunner
+from tests.e2e.conftest import VllmRunner
 from tests.e2e.singlecard.test_ilama_lora import (EXPECTED_LORA_OUTPUT,
                                                   MODEL_PATH, do_sample)