Workaround source-map issue in Node 18

Workaround for mozilla/source-map#454 since we
seem to be hitting this error, causing jest reporting to fail.

package.json

@@ -39,7 +39,7 @@
     "web-ui": "webpack --config components/webpack/webpack.config.js --colors",
     "build-storybook": "build-storybook -c .storybook -o .storybook-out",
     "storybook": "start-storybook",
-    "test-unit": "jest -t",
+    "test-unit": "NODE_OPTIONS=--no-experimental-fetch jest -t",
     "test-unit:wallet": "jest --coverage=false components/brave_wallet_ui",
     "test-python-scripts": "npm run pep8 && PYTHONPATH=./script python -m unittest discover -s ./script/test",
     "update_symlink": "node ./build/commands/scripts/commands.js update_symlink",