Revert "rpcserver: remove uneccessary signal to breacharbiter at force close"

This reverts commit 0f90c950da.

We actually still need to notify the BRAR of a force close, as
otherwise, it doesn't have a signal to exit due to a local force close
event.

rpcserver.go

@@ -1031,6 +1031,12 @@ func (r *rpcServer) CloseChannel(in *lnrpc.CloseChannelRequest,
 			r.server.htlcSwitch.RemoveLink(chanID)
 		}
 
+		select {
+		case r.server.breachArbiter.settledContracts <- *chanPoint:
+		case <-r.quit:
+			return fmt.Errorf("server shutting down")
+		}
+
 		// With the necessary indexes cleaned up, we'll now force close
 		// the channel.
 		chainArbitrator := r.server.chainArb