fix(knowledge recall test): Add system_app parameter to knowledgeSpaceRetriever initialization

[vnicers]

Description

The knowledgebase recall test did not respond to anything, and the log showed an error:
' dbgpt_app.knowledge.service[25544] ERROR recall_test error: 'NoneType' object has no attribute 'config''
and debug the code find missing system_app param

How Has This Been Tested?

Snapshots:

Checklist:

• My code follows the style guidelines of this project
• I have already rebased the commits and make the commit message conform to the project standard.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules

[Aries-ckt]

LGTM

[fangyinc]

LGTM