Update Optional[x] -> x | None and Union[x, y] to x | y (#26633)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/v1/entrypoints/openai/test_completion.py

@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
-from typing import Optional
 
 import openai  # use the official client for correctness check
 import pytest
@@ -195,7 +194,7 @@ async def test_too_many_completion_logprobs(
     [(MODEL_NAME, -1), (MODEL_NAME, 0), (MODEL_NAME, 1), (MODEL_NAME, None)],
 )
 async def test_prompt_logprobs_completion(
-    client: openai.AsyncOpenAI, model_name: str, prompt_logprobs: Optional[int]
+    client: openai.AsyncOpenAI, model_name: str, prompt_logprobs: int | None
 ):
     params: dict = {
         "prompt": ["A robot may not injure another robot", "My name is"],