### What problem does this PR solve?
Add sessions deletion support for agent in http and python api
### Type of change
- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [x] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):
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Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
### What problem does this PR solve?
Update displayed_name to display_name
### Type of change
- [x] Refactoring
Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
### What problem does this PR solve?
Fix bugs in agent api and update api document
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [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 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?
Fix test cases
### Type of change
- [x] Other (please describe): Fix error cases
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Signed-off-by: jinhai <haijin.chn@gmail.com>
### 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>
