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/e2e/test_spec_decode.py

@@ -1,9 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-from __future__ import annotations
-
 import random
-from typing import Any, Union
+from typing import Any
 
 import pytest
 import torch
@@ -34,7 +32,7 @@ def get_test_prompts(mm_enabled: bool):
     for kind in random_prompt_type_choices:
         word_choices = ["test", "temp", "hello", "where"]
         word = random.choice(word_choices)
-        prompt: Union[str, list[dict[str, Any]]] = ""
+        prompt: str | list[dict[str, Any]] = ""
         if kind == "repeat":
             prompt = f"""
             please repeat the word '{word}' 10 times.