chore: Clean up unused files, imports, and work on getting end-to-end tests and unit tests running (#2272)

platform/viewer/src/__mocks__/cornerstone-wado-image-loader.js

@@ -1,5 +0,0 @@
-export default {
-  webWorkerManager: {
-    initialize: jest.fn(),
-  },
-};

platform/viewer/src/__mocks__/redux-oidc.js

@@ -1,4 +0,0 @@
-const createUserManager = () => jest.fn().mockReturnValue({});
-const loadUser = () => jest.fn();
-
-export { createUserManager, loadUser };