src: Addressing comments

- addressed AI comments
- fix tab indexing
- added username to the title of Remove user modal
- ensured "Invalid password" is not in the errors object before a password is filled in
- removing a user with empty user, password and ssh key fields does not prompt "Remove user" modal
- check for duplicate username
- focus on new user tab
- remove redundant tabIndex

src/test/Components/CreateImageWizard/steps/Users/Users.test.tsx

@@ -407,7 +407,7 @@ describe('User request generated correctly', () => {
     await addUserGroupByUserIndex('users', 0);
     await addUserGroupByUserIndex('widget', 0);
     await closeNthTab(0);
-    await waitFor(() => expect(screen.getByText(/add a user to your image/i)));
+    await screen.findByText(/add a user to your image/i);
     await goToReviewStep();
     const receivedRequest = await interceptBlueprintRequest(CREATE_BLUEPRINT);