Sam Figueroa authored Dec 05, 2023 and Jessie Young committed Dec 05, 2023

- Add custom callback controller to handle IdP response

- Refs:
  https://gitlab.com/groups/gitlab-org/-/epics/11084
  https://gitlab.com/gitlab-org/gitlab/-/issues/421959
  https://gitlab.com/gitlab-org/gitlab/-/issues/421961
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/136772
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/136838
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137067#note_1670847259
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137067#note_1670847260
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137067#note_1670847264

Changelog: added
EE: true