fix hidden_layers_sizes config

Author: Ghostvv

docs/migration-guide.rst

@@ -90,7 +90,9 @@ General
     pipeline:
     # - ... other components
     - name: DIETClassifier
-      hidden_layers_sizes: {text: [256, 128]}
+      hidden_layers_sizes:
+        text: [256, 128]
+        label: []
       intent_classification: True
       entity_recognition: False
       use_masked_language_model: False