Update preprocessor_config.json

We don't need to set default for channel format. It is causing issues when a non-last channel image is used

preprocessor_config.json

@@ -17,7 +17,6 @@
     0.5,
     0.5
   ],
-  "input_data_format": "channels_last",
   "max_num_patches": 1024,
   "patch_size": 16,
   "processor_class": "Lfm2VlProcessor",