Remove unused classes in Audit events and Alert details

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/169424



Merged-by: Miranda Fluharty <mfluharty@gitlab.com>
Approved-by: Rajan Mistry <rmistry@gitlab.com>
Approved-by: Miranda Fluharty <mfluharty@gitlab.com>
Co-authored-by: Justin Ho Tuan Duong <hduong@gitlab.com>