Chat UI error when prompt is longer than one character

[faev999]

Hi all, coming from #103 I found yet another error when trying to use the Gradio chat UI:

...python3.12/site-packages/transformers/models/qwen2_vl/processing_qwen2_vl.py", line 137, in __call__
    "<|image_pad|>", "<|placeholder|>" * (image_grid_thw[index].prod() // merge_length), 1
                                          ~~~~~~~~~~~~~~^^^^^^^
IndexError: index 1 is out of bounds for axis 0 with size 1

this happens when the prompt is longer than one character, i.e. if I write "what is this?" the error appears but not when writing just "?"