Make new_project_spec pass with Vite

What does this MR do and why?

ee/spec/features/projects/new_project_spec.rb seems to fail frequently (at least with Vite) because the wait_for_requests called after click_button waits endlessly for all requests to complete. The frontend appears to poll the import status quite frequently, which appears to block wait_for_requests since the import status endpoints may take some time to return.

We have patched Capybara's find_button to wait_for_requests, but in this case it's sufficient to wait for the Complete text to show in the browser.

Relates to #423851 (comment 1822420074)

How to set up and validate locally

With Vite activated in your GDK, run:

bundle exec rspec ee/spec/features/projects/new_project_spec.rb