Fogbugz: Add importing: true to imported events and remove transaction

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144495



Merged-by: Rodrigo Tomonari <rtomonari@gitlab.com>
Approved-by: Michał Zając <mzajac@gitlab.com>
Approved-by: Rodrigo Tomonari <rtomonari@gitlab.com>
Co-authored-by: Ivane Gkomarteli <ivanegkomarteli@Ivanes-MacBook-Pro.local>