Protected packages: Integrate delete protection

In GitLab 17.6, the package protection feature was made generally
available. But, this realease did not include
the deletion package protection,
see https://gitlab.com/gitlab-org/gitlab/-/issues/472655 .

The attribute `minimum_access_level_for_delete` that was introduced
in the MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/179739 .

This attribute is integrated in this MR in order to prevent the deletion
of delete protected packages.

At the moment, the attribute `minimum_access_level_for_delete` cannot be
updated via UI, REST nor GraphQL API. This possibility will be added in
a future iteration.

Changelog: added