Resolve "ActionView::Template::Error: undefined method `human_import_status_name"

What does this MR do?

The Project#human_import_status_name method was provided by https://github.com/state-machines/state_machines, and was inadvertently removed when we moved the import_status state machine from Project to ProjectImportData in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18688.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #47208 (closed)