fix: inference_sample.py

[yufoo1]

Running the inference example from the README directly results in an error:

Traceback (most recent call last):
  File "/workspace/cosmos-reason1/scripts/inference_sample.py", line 92, in <module>
    main()
  File "/workspace/cosmos-reason1/scripts/inference_sample.py", line 65, in main
    image_inputs, video_inputs = qwen_vl_utils.process_vision_info(conversation)
  File "/workspace/cosmos-reason1/.venv/lib/python3.10/site-packages/qwen_vl_utils/vision_process.py", line 517, in process_vision_info
    video_input, video_sample_fps = fetch_video(vision_info, return_video_sample_fps=True,
  File "/workspace/cosmos-reason1/.venv/lib/python3.10/site-packages/qwen_vl_utils/vision_process.py", line 414, in fetch_video
    video, video_metadata, sample_fps = VIDEO_READER_BACKENDS"torchvision"
  File "/workspace/cosmos-reason1/.venv/lib/python3.10/site-packages/qwen_vl_utils/vision_process.py", line 212, in _read_video_torchvision
    total_frames, video_fps = video.size(0), info["video_fps"]
KeyError: 'video_fps'

The error occurs because the root directory path was incorrect. After correcting the root directory, the inference example runs successfully.