fix: typo `doc_metadat` (#14569)

api/core/tools/utils/dataset_retriever/dataset_retriever_tool.py

@@ -172,7 +172,7 @@ class DatasetRetrieverTool(DatasetRetrieverBaseTool):
                                     "segment_id": segment.id,
                                     "retriever_from": self.retriever_from,
                                     "score": record.score or 0.0,
-                                    "doc_metadata": document.doc_metadat,  # type: ignore
+                                    "doc_metadata": document.doc_metadata,  # type: ignore
                                 }
 
                                 if self.retriever_from == "dev":