[test utils] correct wrong typing (vllm-project#26159)

Signed-off-by: Yannick Schnider <[email protected]>

Author: yannicks1

tests/conftest.py

@@ -756,7 +756,7 @@ def __init__(
 
     def get_inputs(
         self,
-        prompts: Union[list[str], list[torch.Tensor], list[int]],
+        prompts: Union[list[str], list[torch.Tensor], list[list[int]]],
         images: Optional[PromptImageInput] = None,
         videos: Optional[PromptVideoInput] = None,
         audios: Optional[PromptAudioInput] = None,