Fix: ensure correct handling of val_set_size as float or int (#1655)

* Fix: ensure correct handling of val_set_size as float or int

* chore: lint

---------

Co-authored-by: Wing Lian <wing.lian@gmail.com>

src/axolotl/utils/data/sft.py

@@ -494,7 +494,9 @@ def load_prepare_datasets(
         test_fingerprint = md5(to_hash_test)
 
         dataset = dataset.train_test_split(
-            test_size=cfg.val_set_size,
+            test_size=int(cfg.val_set_size)
+            if cfg.val_set_size == int(cfg.val_set_size)
+            else cfg.val_set_size,
             shuffle=False,
             seed=cfg.seed or 42,
             train_new_fingerprint=train_fingerprint,