nixos/influx: Fix cross compilation for configFile

nixos/modules/services/databases/influxdb.nix

···
     };
   } cfg.extraConfig;
 
-  configFile = pkgs.runCommandLocal "config.toml" {
-    nativeBuildInputs = [ pkgs.remarshal ];
-  } ''
-    remarshal -if json -of toml \
+  configFile = pkgs.runCommandLocal "config.toml" { } ''
+    ${pkgs.buildPackages.remarshal}/bin/remarshal -if json -of toml \
       < ${pkgs.writeText "config.json" (builtins.toJSON configOptions)} \
       > $out
   '';