Add attribute check to support git-base autotp (#6688)
Git-base model is an image-text model. After supporting the llama3.2
vision model, we set num_kv_heads dynamically.
Git-base only includes vision_config, so we need to add an attribute
check for vision_config/text_config when setting num_kv_heads.
Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
