fix component wiring issue

Author: Thomasr

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/npm/PrivateNpmRegistryController.java

@@ -23,7 +23,7 @@
 public class PrivateNpmRegistryController implements PrivateNpmRegistryEndpoint{
     private final OrganizationService organizationService;
     private final SessionUserService sessionUserService;
-    NodeServerHelper nodeServerHelper;
+    private final NodeServerHelper nodeServerHelper;
 
     private static final String NPM_REGISTRY_METADATA = "npm/registry";
     private static final String NPM_REGISTRY_ASSET = "npm/package";