fix: TypeScript build errors in frontend pipeline

- Remove unused ReactNode import in useAuth.test.tsx
- Use vitest/config for defineConfig to recognize test property
- Add vitest/globals to tsconfig types for test runner globals

Frontend/tsconfig.app.json

@@ -5,7 +5,7 @@
     "useDefineForClassFields": true,
     "lib": ["ES2023", "DOM", "DOM.Iterable"],
     "module": "ESNext",
-    "types": ["vite/client"],
+    "types": ["vite/client", "vitest/globals"],
     "skipLibCheck": true,
 
     /* Bundler mode */