Fix build issue

Author: jahn96

package.json

@@ -74,7 +74,9 @@
     "@lumino/messaging": "^1.4.3",
     "@lumino/properties": "^1.2.3",
     "@lumino/signaling": "^1.4.3",
-    "@lumino/widgets": "^1.36.0"
+    "@lumino/widgets": "^1.36.0",
+    "@types/react": "^16.9.56",
+    "@types/react-dom": "^16.9.9"
   },
   "devDependencies": {
     "@babel/core": "^7",
@@ -87,8 +89,6 @@
     "@types/enzyme-adapter-react-16": "^1.0.6",
     "@types/jest": "^26.0.15",
     "@types/node-fetch": "^2.5.7",
-    "@types/react": "^16.9.56",
-    "@types/react-dom": "^16.9.9",
     "@types/react-test-renderer": "^16.9.3",
     "@typescript-eslint/eslint-plugin": "^4.8.1",
     "@typescript-eslint/parser": "^4.8.1",