Folders: Fix folder pagination for cloud instances with many folders (#90008)

* filter the k6 folder out in the SQL queries rather than during post processing to ensure that the correct number of results is always returned

* linting

pkg/services/folder/folderimpl/folder.go

@@ -180,17 +180,7 @@ func (s *Service) GetFolders(ctx context.Context, q folder.GetFoldersQuery) ([]*
 		}
 	}
 
-	// only list k6 folders when requested by a service account - prevents showing k6 folders in the UI for users
-	result := make([]*folder.Folder, 0, len(dashFolders))
-	requesterIsSvcAccount := qry.SignedInUser.GetID().Namespace() == identity.NamespaceServiceAccount
-	for _, folder := range dashFolders {
-		if (folder.UID == accesscontrol.K6FolderUID || folder.ParentUID == accesscontrol.K6FolderUID) && !requesterIsSvcAccount {
-			continue
-		}
-		result = append(result, folder)
-	}
-
-	return result, nil
+	return dashFolders, nil
 }
 
 func (s *Service) Get(ctx context.Context, q *folder.GetFolderQuery) (*folder.Folder, error) {