Fix Netlify build error - add missing react-beautiful-dnd dependency

- Added react-beautiful-dnd@^13.1.1 to package.json dependencies
- Fixes build failure in DocumentGenerator.js component
- Netlify deployment should now succeed

Author: BTheCoderr

frontend/package.json

@@ -37,6 +37,7 @@
     "notistack": "^3.0.2",
     "pdfjs-dist": "^5.2.133",
     "react": "^18.2.0",
+    "react-beautiful-dnd": "^13.1.1",
     "react-chartjs-2": "^5.2.0",
     "react-dom": "^18.2.0",
     "react-error-boundary": "^5.0.0",