Omit files for more correct progress bar

[bart1]

bird-cloud-gnn/bird_cloud_gnn/radar_dataset.py

Line 292 in 0ad3dfc

data_files = sorted(os.listdir(self.data_path))

It would be good here to omit *.bin and *.pkl files as those are the cache files now each time reading is attempted while they are not valid input files