Direct Transfer - merge request pipeline widget not loading when last MR pipeline was in pending status

Imported project merge requests with a last pipeline in pending status are unable to display pipeline widget in merge request page. Widget is loading indefinitely.

The pipelines tab displays all the pipelines correctly and upon pushing new commit new pipeline will be triggered correctly as well and widget will start to work.

The issue is probably with missing some type of parameter that prevents widget from fetching last pipeline.

Steps to reproduce

1. Ensure that your localhost does not have gitlab-runner running. If necessary do: gitlab-running stop (see GDK runner docs)
2. Create a project
3. Add a basic .gitlab-ci.yml file from the example https://docs.gitlab.com/ci/quick_start/#create-a-gitlab-ciyml-file, create a MR to merge this change back to main
4. A pipeline will start when the MR is created in pending status
5. Import the group/project using Direct Transfer (do a localhost -> localhost transfer)
6. The imported MR will have the problem

Proposal

From #433096 (comment 1923719254):

Export the merge_request.head_pipeline as a whole, similarly to how we export merge_request as part of the CI pipeline.

We'd have to update Gitlab::ImportExport::Project::ObjectBuilder to ensure we don't create duplicate CI pipelines.