Fixes SDK large DF input issue

This should ideally use the same data observability introspection
code path. It doesn't. So this is a stop gap measure to log the
head rows of a dataframe if you use one as input.

ui/sdk/src/hamilton_sdk/tracking/utils.py

@@ -47,6 +47,8 @@ def make_json_safe(item: Union[dict, list, str, float, int, bool]) -> Any:
     elif hasattr(item, "to_json"):
         # we convert to json string and then deserialize it so that
         # it's not a string in the UI.
+        if hasattr(item, "head"):
+            item = item.head()  # truncate to head rows if it's a dataframe
         try:
             return json.loads(item.to_json())
         except Exception:

ui/sdk/tests/tracking/test_utils.py

@@ -139,7 +139,7 @@ def test_make_json_safe_with_pandas_series():
         "1642291200000": 50,
         "1642896000000": 100,
         "1643500800000": 200,
-        "1644105600000": 400,
+        # "1644105600000": 400, -- skipped due to `.head()` being called
     }