devfront vitest 커버리지 오류 수정

devfront/src/features/auth/authPages.test.tsx

@@ -26,6 +26,7 @@ vi.mock("react-oidc-context", () => ({
 
 vi.mock("../../lib/auth", () => ({
   userManager: {
+    getUser: vi.fn(async () => undefined),
     signinPopupCallback: vi.fn(async () => undefined),
   },
 }));