feat(ci): replace jest with vitest [EE-6504] (#10997)

app/setup-tests/jest-polyfills.ts

@@ -1,42 +0,0 @@
-/* eslint-disable import/order */
-/* eslint-disable @typescript-eslint/no-var-requires */
-/**
- * @note The block below contains polyfills for Node.js globals
- * required for Jest to function when running JSDOM tests.
- * These HAVE to be require's and HAVE to be in this exact
- * order, since "undici" depends on the "TextEncoder" global API.
- *
- * Consider migrating to a more modern test runner if
- * you don't want to deal with this.
- */
-// eslint-disable-next-line @typescript-eslint/ban-ts-comment
-// @ts-ignore
-const { TextDecoder, TextEncoder } = require('node:util');
-
-Object.defineProperties(globalThis, {
-  TextDecoder: { value: TextDecoder },
-  TextEncoder: { value: TextEncoder },
-});
-
-const { ReadableStream } = require('node:stream/web');
-
-Object.defineProperties(globalThis, {
-  ReadableStream: { value: ReadableStream },
-});
-
-const { Blob, File } = require('node:buffer');
-
-const { fetch, Headers, FormData, Request, Response } = require('undici');
-
-Object.defineProperties(globalThis, {
-  fetch: { value: fetch, writable: true },
-  Blob: { value: Blob },
-  File: { value: File },
-  Headers: { value: Headers },
-  FormData: { value: FormData },
-  Request: { value: Request },
-  Response: { value: Response },
-});
-
-/* eslint-enable @typescript-eslint/no-var-requires */
-/* eslint-enable import/order */

app/setup-tests/setup-msw.ts

@@ -1,5 +1,3 @@
-// test/setup-env.js
-// add this to your setupFilesAfterEnv config in jest so it's imported for every test file
 import { server } from './server';
 
 beforeAll(() => server.listen());