fix(meta): Only define targetHost when the network config is defined

meta/options.nix

@@ -205,11 +205,12 @@ in
             config = {
               deployment = {
                 tags = [ "infra-${config.site}" ];
-                targetHost =
+                targetHost = mkIf (builtins.hasAttr name args.config.network) (
                   let
                     ip = with args.config.network.${name}.addresses; ipv4 ++ ipv6;
                   in
-                  mkIf (ip != [ ]) (mkDefault (builtins.head ip));
+                  mkIf (ip != [ ]) (mkDefault (builtins.head ip))
+                );
               };
             };
           }