chore: set unused vars to error (#768)

Author: marthayaputra

.eslintrc.json

@@ -16,6 +16,7 @@
   ],
   "rules": {
     "@typescript-eslint/no-var-requires": "off",
+    "@typescript-eslint/no-unused-vars": "error",
     "@typescript-eslint/explicit-function-return-type": "off",
     "@typescript-eslint/no-explicit-any": "off",
     "react/no-find-dom-node": "off",