Allow X-HF-Bill-To header for all deployments (#2054)
Allow X-HF-Bill-To header for all deployments, not just HuggingChat
This enables users with local Chat-UI deployments to bill inference
usage to their HuggingFace organization by removing the isHuggingChat
restriction on the X-HF-Bill-To header.
Fixes #1986
Co-authored-by: gary149 <gary149@users.noreply.github.com>