Fix artifact initialization dict creation to be recursive

Signed-off-by: Elron Bandel <elron.bandel@ibm.com>

src/unitxt/artifact.py

@@ -207,7 +207,7 @@ def verify(self):
 
     @final
     def __pre_init__(self, **kwargs):
-        self._init_dict = deepcopy(kwargs)
+        self._init_dict = deepcopy(get_raw(kwargs))
 
     @final
     def __post_init__(self):
@@ -232,6 +232,16 @@ def save(self, path):
         save_json(path, data)
 
 
+def get_raw(element):
+    if isinstance(element, Artifact):
+        return element._to_raw_dict()
+    if isinstance(element, (list, tuple)):
+        return [get_raw(sub_element) for sub_element in element]
+    if isinstance(element, dict):
+        return {key: get_raw(value) for key, value in element.items()}
+    return element
+
+
 class ArtifactList(list, Artifact):
     def prepare(self):
         for artifact in self: