Add empty repo check in DetectAndHandleSchedules (#29606) (#29659)

Backport #29606

services/actions/notifier_helper.go

@@ -459,6 +459,10 @@ func handleSchedules(
 
 // DetectAndHandleSchedules detects the schedule workflows on the default branch and create schedule tasks
 func DetectAndHandleSchedules(ctx context.Context, repo *repo_model.Repository) error {
+	if repo.IsEmpty {
+		return nil
+	}
+
 	gitRepo, err := git.OpenRepository(context.Background(), repo.RepoPath())
 	if err != nil {
 		return fmt.Errorf("git.OpenRepository: %w", err)