chore: Skip reading external blocks in NotionConnector

The commit skips reading 'external_object_instance_page' blocks in the NotionConnector due to the lack of support in the Notion API. This change is in response to the issue danswer-ai#1761.

backend/danswer/connectors/notion/connector.py

@@ -237,6 +237,13 @@ def _read_blocks(
                     )
                     continue
 
+                if result_type == "external_object_instance_page":
+                    logger.warning(
+                        f"Skipping 'external_object_instance_page' ('{result_block_id}') for base block '{base_block_id}': "
+                        f"Notion API does not currently support reading external blocks (as of 24/07/03) "
+                        f"(discussion: https://github.com/danswer-ai/danswer/issues/1761)")
+                    continue
+
                 cur_result_text_arr = []
                 if "rich_text" in result_obj:
                     for rich_text in result_obj["rich_text"]: