[data] Fix valset loading for videos (#482)

Author: zhuohaoyu

verl/trainer/data_loader.py

@@ -72,7 +72,9 @@ def create_dataloader(config: DataConfig, tokenizer: PreTrainedTokenizer, proces
         prompt_key=config.prompt_key,
         answer_key=config.answer_key,
         image_key=config.image_key,
+        video_key=config.video_key,
         image_dir=config.image_dir,
+        video_fps=config.video_fps,
         max_prompt_length=config.max_prompt_length,
         truncation="right",
         format_prompt=config.format_prompt,