Migrate more tests to vitest (#34355)

* Remove doubled-up I18n Provider. ModalManager already provides this.

* Reconfigure svgr into a vite-friendly `?react` resource query

* Move InviteDialog test to vitest

* Move RoomHeader tests to Vitest

* Share serializer between Jest & Vitest

* Attempt to stabilise InviteDialog test

* Fix async leaks

* Migrate more tests to vitest

* Migrate MatrixChat test to vitest

* Deflake

* Iterate

* Iterate

* Iterate

apps/web/__mocks__/workerFactoryMock.js

@@ -9,5 +9,7 @@ Please see LICENSE files in the repository root for full details.
 import { vi } from "vitest";
 
 export default function workerFactory(options) {
-    return vi.fn;
+    return {
+        postMessage: vi.fn(),
+    };
 }