### What problem does this PR solve?
The knowledge_graph chunk method is deprecated and should no longer be
used. #7184.
### Type of change
- [x] Refactoring
### What problem does this PR solve?
Add sdk for list agents and sessions
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
### What problem does this PR solve?
Add tests for frontend API
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
---------
Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
