Fix yolo mode=train CLI bug on model load (#133)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/yolo/engine/trainer.py

@@ -362,7 +362,7 @@ class BaseTrainer:
             return
             # We should improve the code flow here. This function looks hacky
         model = self.model
-        pretrained = not (str(model).endswith(".yaml"))
+        pretrained = not str(model).endswith(".yaml")
         # config
         if not pretrained:
             model = check_file(model)