handle empty doc batches (#5058)

.vscode/launch.template.jsonc

@@ -428,7 +428,7 @@
       },
       "args": [
         "--filename",
-        "generated/openapi.json",
+        "generated/openapi.json"
       ]
     },
     {

backend/onyx/background/indexing/run_docfetching.py

@@ -1146,7 +1146,7 @@ def connector_document_extraction(
                     checkpoint = next_checkpoint
 
                 # below is all document processing task, so if no batch we can just continue
-                if document_batch is None:
+                if not document_batch:
                     continue
 
                 # Clean documents and create batch