### Summary
As title
Before, it return `update success` but never insert or update any
metadata
fixed:
```go
_, err = s.docEngine.InsertMetadata(nil, []map[string]interface{}{
{
"id": docID,
"kb_id": doc.KbID,
"meta_fields": meta,
},
}, tenantID)
```
ee45c97b0b