fix: fix corner case in LabelingTaskGenerator._load_metadata
fix: fix corner case in LabelingTaskGenerator._load_metadata

Co-authored-by: Hervé BREDIN <c8d67b9325bd7ee39e39c57722a66264fadfbd8b@users.noreply.github.com>
pyannote/pyannote-audio,pyannote/pyannote-audio,pyannote/pyannote-audio