Unquarantine npm_group_pkgs_spec with fix

What does this MR do and why?

Resolves flaky spec reported in #418757 (closed).

This is a similar fix as Unquarantine project service blob and commit (!128052 - closed)

Due to https://gitlab.com/gitlab-org/gitlab/-/blob/3b49bb38ccf1b9138f4bd70a275c0d3352c59727/spec/requests/api/npm_group_packages_spec.rb#L120:

project.update!(visibility: project_visibility.to_s)

project is being mutated in this step, so the shared project record risks leaking state. This should be mitigated by switching to let_it_be(:project, refind: true).

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.