TUN-6720: Remove forcibly closing connection during reconnect signal

Previously allowing the reconnect signal forcibly close the connection
caused a race condition on which error was returned by the errgroup
in the tunnel connection. Allowing the signal to return and provide
a context cancel to the connection provides a safer shutdown of the
tunnel for this test-only scenario.

supervisor/supervisor.go

@@ -295,8 +295,7 @@ func (s *Supervisor) initialize(
 			s.config.ProtocolSelector.Current(),
 			false,
 		}
-		ch := signal.New(make(chan struct{}))
-		go s.startTunnel(ctx, i, ch)
+		go s.startTunnel(ctx, i, s.newConnectedTunnelSignal(i))
 		time.Sleep(registrationInterval)
 	}
 	return nil