hs: Return the 0xF6 extended socks error for a v2

In #40373 (closed), we made it that a v2 address is properly parsed and then a warning is logged indicating that it is not supported anymore.

Problem is that we failed to send back a 0xF6 extended socks error code so Tor Browser UX is better. At the moment, we just close the stream and thus TB gets "Unable to connect".