[Bugfix] Fix mypy errors for StructuredOutputsParams by using stdlib dataclass#34693

hyeongyun0916 wants to merge 5 commits intovllm-project:mainvllm-project/vllm:mainfrom

moreh-dev:fix-pre-commit-dataclassmoreh-dev/vllm:fix-pre-commit-dataclassCopy head branch name to clipboard