relay: Send back CONNECTION_REFUSED on reentry
The TORPROTOCOL reason causes the client to close the circuit which is not what we want because other valid streams might be on it.
Instead, CONNECTION_REFUSED will leave it open but will not allow more streams to be attached to it. The client then open a new circuit to the destination.
Closes #40270 (closed)
Signed-off-by: David Goulet firstname.lastname@example.org