add av_odyssey bench

[Bohao-Lee]

We introduce the av_odyssey benchmark, designed to evaluate a model's audio-visual capabilities.

Currently, we provide an implementation based on the Gemini model. The corresponding command to run the evaluation is as follows:

accelerate launch --num_processes 8 --main_process_port 12345 -m lmms_eval --model gemini_api --tasks av_odyssey --batch_size 1  --log_samples_suffix av_odyssey --output_path ./logs/

To support this evaluation, we made modifications to the gemini_api.py file located in the models directory.