refactor: Change Node::initError to take bilingual_str

Make it consistent with `Chain::initError`.

src/interfaces/node.cpp

@@ -56,7 +56,7 @@ namespace {
 class NodeImpl : public Node
 {
 public:
-    void initError(const std::string& message) override { InitError(Untranslated(message)); }
+    void initError(const bilingual_str& message) override { InitError(message); }
     bool parseParameters(int argc, const char* const argv[], std::string& error) override
     {
         return gArgs.ParseParameters(argc, argv, error);