<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=576100) </details> <!--IssueSummary end--> Similar to `BulkImport`s, users should be able to cancel in-progress `Import::Offline::Export`s by calling an API endpoint similar to [`POST /bulk_imports/:id/cancel`](https://docs.gitlab.com/api/bulk_imports/#cancel-a-migration). This action should prevent any new exports from taking place and mark the `Import::Offline::Export` record as cancelled.