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/models/language/pooling/test_embedding.py

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-from typing import Optional
 
 import pytest
 
@@ -66,7 +65,7 @@ def test_models(
             pooling_type="MEAN", normalize=False
         )
 
-    max_model_len: Optional[int] = 512
+    max_model_len: int | None = 512
     if model in [
         "sentence-transformers/all-MiniLM-L12-v2",
         "sentence-transformers/stsb-roberta-base-v2",