Fix flaky test

What does this MR do and why?

Pins the project_statistic traversal ids to original_parent_group, because the factory default read the in-memory project.namespace, which an earlier example had already moved to new_parent_group. This makes the service hit its early-return guard. This also removes the quarantine.

Closes https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/10451.

Changelog: fixed EE: true

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