docs: add jest-environment-jsdom package for Jest configuration (#36632)

## Documentation / Examples

- [ ] Make sure the linting passes by running `yarn lint`

Jest 28 does not include jest-environment-jsdom by default.

following guide & running jest without jest-environment-jsdom causes the following  error:

<img width="1598" alt="image" src="https://user-images.githubusercontent.com/37980706/166319065-2bc29bb4-7d56-43e5-b85d-5a7484f17b1b.png">

docs/testing.md

@@ -263,10 +263,10 @@ npx create-next-app@latest --example with-jest with-jest-app
 
 Since the release of [Next.js 12](https://nextjs.org/blog/next-12), Next.js now has built-in configuration for Jest.
 
-To set up Jest, install `jest` , `@testing-library/react`, `@testing-library/jest-dom`:
+To set up Jest, install `jest`, `jest-environment-jsdom`, `@testing-library/react`, `@testing-library/jest-dom`:
 
 ```bash
-npm install --save-dev jest @testing-library/react @testing-library/jest-dom
+npm install --save-dev jest jest-environment-jsdom @testing-library/react @testing-library/jest-dom
 ```
 
 Create a `jest.config.js` file in your project's root directory and add the following: