fix: Replace alpha import with stable version for scaffolder-backend

Co-authored-by: johnnyhuy <27847622+johnnyhuy@users.noreply.github.com>

Author: Copilot

packages/backend/src/index.ts

@@ -4,7 +4,7 @@ const backend = createBackend();
 
 backend.add(import('@backstage/plugin-app-backend'));
 backend.add(import('@backstage/plugin-proxy-backend'));
-backend.add(import('@backstage/plugin-scaffolder-backend/alpha'));
+backend.add(import('@backstage/plugin-scaffolder-backend'));
 backend.add(import('@backstage/plugin-scaffolder-backend-module-github'));
 backend.add(import('@backstage/plugin-scaffolder-backend-module-gitlab'));
 backend.add(import('@backstage/plugin-techdocs-backend/alpha'));