Use the default import path for jest-dom.

ui/src/common/Linkify.test.js

@@ -1,6 +1,6 @@
 import React from 'react'
 import { render, screen } from '@testing-library/react'
-import '@testing-library/jest-dom/extend-expect'
+import '@testing-library/jest-dom'
 import Linkify from './Linkify'
 
 const URL = 'http://www.example.com'

ui/src/setupTests.js

@@ -2,7 +2,7 @@
 // allows you to do things like:
 // expect(element).toHaveTextContent(/react/i)
 // learn more: https://github.com/testing-library/jest-dom
-import '@testing-library/jest-dom/extend-expect'
+import '@testing-library/jest-dom'
 
 const localStorageMock = (function () {
   let store = {}