[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>
### What problem does this PR solve?
Removed set_entity and set_relation to avoid accessing doc engine during
graph computation.
Introduced GraphChange to avoid writing unchanged chunks.
### Type of change
- [x] Performance Improvement
### What problem does this PR solve?
1. miss completion delimiter.
2. miss bracket process.
3. doc_ids return by update_graph is a set, and insert operation in
extract_community need a list.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
