Revert "Do not serializer.load_params_from_definition in sk_params"

This reverts commit 65c290c.

gordo/machine/model/models.py

@@ -177,7 +177,7 @@ def sk_params(self):
         fit_args = self.extract_supported_fit_args(self.kwargs)
         if fit_args:
             kwargs = deepcopy(self.kwargs)
-            kwargs.update(fit_args)
+            kwargs.update(serializer.load_params_from_definition(fit_args))
             return kwargs
         else:
             return self.kwargs

gordo/serializer/from_definition.py

@@ -5,6 +5,8 @@
 import typing  # noqa
 
 from typing import Union, Dict, Any, Iterable
+
+from keras.src.callbacks import Callback
 from sklearn.pipeline import Pipeline, FeatureUnion
 from sklearn.base import BaseEstimator
 from tensorflow.keras import Sequential
@@ -365,5 +367,7 @@ def build_callbacks(definitions: list):
     """
     callbacks = []
     for callback in definitions:
-        callbacks.append(_build_step(callback))
+        callbacks.append(
+            callback if isinstance(callback, Callback) else _build_step(callback)
+        )
     return callbacks