fix(dataset): join data_folder with video path in Qwen3VL iterable dataset#152

kcz358 merged 1 commit intomainEvolvingLMMs-Lab/lmms-engine:mainfrom

fix/qwen3-vl-video-path-data-folderEvolvingLMMs-Lab/lmms-engine:fix/qwen3-vl-video-path-data-folderCopy head branch name to clipboard