[Engine]Refactor output processing for multimodal capabilities in vLLM-omni#20

hsliuustc0106 merged 2 commits into

vllm-project:mainvllm-project/vllm-omni:mainfrom

tzhouam:feat/multimodal-output-processortzhouam/vllm-omni-pre-release:feat/multimodal-output-processorCopy head branch name to clipboard