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

@@ -30,12 +30,12 @@ dataset_info:
   - name: metadata_path_len
     dtype: int32
   splits:
-  - name: test
-    num_bytes: 1532223
-    num_examples: 3003
   - name: train
     num_bytes: 17089298
     num_examples: 29808
+  - name: test
+    num_bytes: 1532223
+    num_examples: 3003
   - name: validation
     num_bytes: 3779584
     num_examples: 6894