Overwrite image and audio cached assets when necessary
Currently we never overwrite image and audio cached assets, which can lead to outdated data in the viewer like here:
https://huggingface.co/datasets/ccmusic-database/instrument_timbre_eval/discussions/1

In particular we have `overwrite=False` here:

https://github.com/huggingface/datasets-server/blob/b84c8210ec023664c4780ab348b0232468afe116/libs/libapi/src/libapi/response.py#L36-L42

cc @AndreaFrancis @severo 
Overwrite image and audio cached assets when necessary: Currently we never overwrite image and audio cached assets, which can lead to outdated data in the viewer like here:
https://huggingface.co/datasets/ccmusic-database/instrument_timbre_eval/discussions/1

In particular we have `overwrite=False` here:

https://github.com/huggingface/datasets-server/blob/b84c8210ec023664c4780ab348b0232468afe116/libs/libapi/src/libapi/response.py#L36-L42

cc @AndreaFrancis @severo 