Removes spyon in alert_details_spec

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/139601



Merged-by: Phil Hughes <me@iamphill.com>
Approved-by: Vamsi Vempati <vvempati@gitlab.com>
Approved-by: Phil Hughes <me@iamphill.com>
Reviewed-by: Vamsi Vempati <vvempati@gitlab.com>
Co-authored-by: Artur Fedorov <afedorov@gitlab.com>