When loading another space using load, allow accessing private demos

[osanseviero]

The api_key is already a valid parameter (used for the Inference API integration). It would be great if this could be used to access private spaces as well :)

[abidlabs]

Definitely would be good to support this. @XciD if you could kindly share a usage example of how to use the Hub token to access Private Spaces, we can integrate this into the library itself.

[XciD]

@abidlabs you need to send the auth token link auth header:
Authorization: Bearer hf_token

[abidlabs]

Thanks got it @XciD!