Reorder split names

Reorder split names in the YAML metadata to be aligned with the order in the loading script.
See: https://github.com/huggingface/datasets/issues/5258

README.md

@@ -30,15 +30,15 @@ dataset_info:
   - name: subject_line
     dtype: string
   splits:
-  - name: test
-    num_bytes: 1384177
-    num_examples: 1906
   - name: train
     num_bytes: 11902668
     num_examples: 14436
   - name: validation
     num_bytes: 1660730
     num_examples: 1960
+  - name: test
+    num_bytes: 1384177
+    num_examples: 1906
   download_size: 11643743
   dataset_size: 14947575
 ---