Merge branch 'schmil-remove-index_vulnerability_occurrences_on_primary_identifier_id' into 'master' 

Remove index_vulnerability_occurrences_on_primary_identifier_id

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/157283



Merged-by: Marius Bobin <mbobin@gitlab.com>
Approved-by: Marius Bobin <mbobin@gitlab.com>
Reviewed-by: Marius Bobin <mbobin@gitlab.com>
Co-authored-by: Schmil Monderer <smonderer@gitlab.com>