Do not read clinical file as str

dataset.py

@@ -88,7 +88,7 @@ class NumpyCSVDataset(Dataset):
 
         np.random.seed(self.seed)
 
-        clinical = pd.read_csv(clinical_file, dtype=str).sort_values(by=['patient'])
+        clinical = pd.read_csv(clinical_file).sort_values(by=['patient'])
 
         available_files = [f for f in os.listdir(data_dir) if f.endswith('.npy')]