Allow deleting completed access review campaigns

Completed campaigns were immutable because delete only accepted draft
or cancelled status. Extend deletion to completed records and surface
delete in the console for that status.

Signed-off-by: Cursor Agent <cursoragent@cursor.com>

Co-authored-by: Bryan FRIMIN <bryan@frimin.fr>

pkg/accessreview/campaign_service.go

@@ -206,7 +206,8 @@ func (s *Service) DeleteCampaign(
 			}
 
 			if campaign.Status != coredata.AccessReviewCampaignStatusDraft &&
-				campaign.Status != coredata.AccessReviewCampaignStatusCancelled {
+				campaign.Status != coredata.AccessReviewCampaignStatusCancelled &&
+				campaign.Status != coredata.AccessReviewCampaignStatusCompleted {
 				return NewCampaignNotDeletableError(campaign.ID)
 			}