Include bridge fingerprint in Snowflake params
Tor Browser includes the bridge fingerprint in the key=value params passed to the Snowflake process, but Briar doesn't. Currently this doesn't matter because the Snowflake binary includes a default fingerprint that's the same as the one Tor Browser passes. But we should probably match what Tor Browser is doing so we don't get any surprises if the bridge fingerprint changes.
This would involve adding the fingerprint to the key=value params and removing one of the STUN servers, to keep the total length of the params within the limit.