Move some of the slowest tests from jest to vitest (#34277)

* 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

* Iterate based on copilot review

* Fix InviteDialog throttle

* Iterate

* Apply suggestions from code review

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* Fix lockfile

* Iterate

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

apps/web/__mocks__/svg-react.js

@@ -0,0 +1,8 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+export default "div";

apps/web/__mocks__/svg.js

@@ -5,5 +5,4 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-export const Icon = "div";
 export default "image-file-stub";