[When parsing documents with graph, an error
occurred:[ERROR][Exception]: 'method']
(https://github.com/infiniflow/ragflow/issues/6835)
### What problem does this PR solve?

Close #6786

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

Co-authored-by: cm <caiming@sict.ac.cn>