fix(node-gateway): fix nix build

Author: JitpanuM

packaging/nix/grpc_server_reflection.nix

@@ -1,6 +1,7 @@
 # SPDX-FileCopyrightText: 2025 Institute for Automation of Complex Power Systems, RWTH Aachen University
 # SPDX-License-Identifier: Apache-2.0
 {
+  lib,
   stdenv,
   fetchurl,
   protobuf,
@@ -22,7 +23,7 @@ stdenv.mkDerivation {
     # Create a temporary build directory
     mkdir -p tmp
     ln -s $src tmp/reflection.proto
-
+    export LD_LIBRARY_PATH="${lib.makeLibraryPath [ protobuf grpc ]}:$LD_LIBRARY_PATH"
     # Generate code into build_tmp
     protoc --cpp_out=tmp \
            --grpc_out=tmp \