Alerting: Drop NamespaceID from responses on unstable ngalert API endpoints in favor of NamespaceUID (#79359)

* Drop from API response

* Drop from swagger docs

* Drop from integration tests

* regenerate public swagger docs

* Drop from frontend

* Drop asserts for namespaceID field

pkg/services/ngalert/store/alert_rule.go

@@ -460,7 +460,6 @@ func (st DBstore) GetUserVisibleNamespaces(ctx context.Context, orgID int64, use
 				continue
 			}
 			namespaceMap[hit.UID] = &folder.Folder{
-				ID:    hit.ID, // nolint:staticcheck
 				UID:   hit.UID,
 				Title: hit.Title,
 			}