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

@@ -29,12 +29,12 @@ dataset_info:
   - name: example
     dtype: string
   splits:
-  - name: test
-    num_bytes: 39712
-    num_examples: 2170
   - name: train
     num_bytes: 321134
     num_examples: 17572
+  - name: test
+    num_bytes: 39712
+    num_examples: 2170
   - name: validation
     num_bytes: 36018
     num_examples: 1953