Migrate from Jest to Vitest

This migrates our tests from using the Jest testing framework to Vitest.

src/test/setup.ts

@@ -0,0 +1,5 @@
+import { server } from './mocks/server';
+
+beforeAll(() => server.listen({ onUnhandledRequest: 'error' }));
+afterAll(() => server.close());
+afterEach(() => server.resetHandlers());