Address PR comment

Author: Kevin Kim

labelbox/schema/dataset.py

@@ -344,10 +344,10 @@ def convert_item(item):
 
         # TODO: If any datarows contain metadata, we're limiting max # of datarows
         # until we address performance issues with datarow create with metadata
-        max_datarow_with_metadata = 30000
+        max_datarow_with_metadata = 2
         if (len(items) > max_datarow_with_metadata):
             for row in items:
-                if row.get("metadata_fields"):
+                if 'metadata_fields' in row:
                     raise ValueError(
                         f"Cannot create more than {max_datarow_with_metadata} DataRows, if any DataRows contain metadata"
                     )