Allow BandwidthFile's `node_id` KeyValue without dollar sign at the start of the hexdigit

Most (if not all) of the documents that tor generates don't have relays' fingerprints starting with the dollar sign anymore. Now that we start to have databases from the documents, removing the dollar sign would easier the databases' queries.

This change requires modifying tor code.

Needed for tpo/network-health/sbws#40177 (closed)