Prep for future breaking changes in newer versions of transformers library

toolkit/reference_adapter.py

@@ -30,9 +30,6 @@ from transformers import (
 )
 from toolkit.models.size_agnostic_feature_encoder import SAFEImageProcessor, SAFEVisionModel
 
-from transformers import ViTHybridImageProcessor, ViTHybridForImageClassification
-
-from transformers import ViTFeatureExtractor, ViTForImageClassification
 
 import torch.nn.functional as F
 import torch.nn as nn