we don't need to call check_dataset_labels when skip_prepare_dataset is set (#2962)

* we don't need to call check_dataset_labels when skip_prepare_dataset is set

* Fix actual bug and revert prior fix

* warn and early return instead of raising an error

* use error

src/axolotl/cli/preprocess.py

@@ -37,10 +37,11 @@ def do_preprocess(cfg: DictDefault, cli_args: PreprocessCliArgs) -> None:
     check_user_token()
 
     for key in ["skip_prepare_dataset", "pretraining_dataset"]:
-        if cfg.get("key"):
-            raise ValueError(
+        if cfg.get(key):
+            LOG.error(
                 f"You have set `{key}:`. `preprocess` is not needed. Run the `axolotl train` CLI directly instead."
             )
+            return
 
     if not cfg.dataset_prepared_path:
         msg = (