SkipLink: update test setup to use testutils

Author: clairep94

client/components/SkipLink.test.tsx

@@ -1,15 +1,7 @@
-import { render, screen, fireEvent } from '@testing-library/react';
 import React from 'react';
-import { useTranslation } from 'react-i18next';
-import '@testing-library/jest-dom';
+import { render, screen, fireEvent } from '../test-utils';
 import { SkipLink } from './SkipLink';
 
-jest.mock('react-i18next', () => ({
-  useTranslation: () => ({
-    t: (key: string) => key
-  })
-}));
-
 describe('SkipLink', () => {
   const defaultProps = {
     targetId: 'main-content',