remove unstructured api key check (#18989)

api/core/workflow/nodes/document_extractor/node.py

     """
     from unstructured.partition.api import partition_via_api
 
-    if not (dify_config.UNSTRUCTURED_API_URL and dify_config.UNSTRUCTURED_API_KEY):
-        raise TextExtractionError("UNSTRUCTURED_API_URL and UNSTRUCTURED_API_KEY must be set")
+    if not dify_config.UNSTRUCTURED_API_URL:
+        raise TextExtractionError("UNSTRUCTURED_API_URL must be set")
 
     try:
         with tempfile.NamedTemporaryFile(suffix=".doc", delete=False) as temp_file:
                     file=file,
                     metadata_filename=temp_file.name,
                     api_url=dify_config.UNSTRUCTURED_API_URL,
-                    api_key=dify_config.UNSTRUCTURED_API_KEY,
+                    api_key=dify_config.UNSTRUCTURED_API_KEY,  # type: ignore
                 )
             os.unlink(temp_file.name)
         return "\n".join([getattr(element, "text", "") for element in elements])