Moves related issues

What does this MR do?

Duplicates "related issues" when moving an issue

This merge request is built on top of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/15391.

Related to https://gitlab.com/gitlab-org/gitlab-ee/issues/13632

Screenshots

Old issue on project-a (before move)	Old issue on project-a (after move)	New issue on project-b

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers