Create E2E test for User membership mapping feature of Direct transfer
<!--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=537230) </details> <!--IssueSummary end--> Based on this [conversation](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/166658#note_2197882357), There is a "Import User memberships" checkbox on the Import page which might need an E2E test. But I need to gather more information on this to continue. Currently we have E2E API based test for group member and project member imports -https://gitlab.com/gitlab-org/gitlab/-/blob/master/qa/qa/specs/features/api/1_manage/migration/gitlab_migration_members_spec.rb
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