u9fs service: start after network.target

nixos/modules/services/network-filesystems/u9fs.nix

@@ -55,6 +55,7 @@ in
       sockets.u9fs = {
         description = "U9fs Listening Socket";
         wantedBy = [ "sockets.target" ];
+        after = [ "network.target" ];
         inherit (cfg) listenStreams;
         socketConfig.Accept = "yes";
       };