A defs: fix path for sound dataset (#3438)

Author: eaidova

data/dataset_definitions.yml

@@ -1254,7 +1254,7 @@ datasets:
     dataset_meta: antispoofing.json
 
   - name: sound_classification
-    data_source: audio_dataset
+    data_source: audio_dataset/data
     annotation_conversion:
       converter: sound_classification
       annotation_file: audio_dataset/validation.csv