chore: Remove unused fetch-mock imports from app tests

Cleaned up app.test.ts by removing unused fetch-mock-jest imports and calls. This prepares the file for future test implementations.

Author: rohit1901

lib/__tests__/app.test.ts

@@ -1,3 +1 @@
-import fetchMock from "fetch-mock-jest";
 // TODO: Add tests
-fetchMock.sandbox();