Fix potential mass deletion when kb_id is empty in /rm endpoint

[lianwenke]

What problem does this PR solve? #7095

• This PR addresses a critical bug where passing an empty kb_id ("") to the /rm endpoint could result in deletion of all knowledgebases owned by the current user.

• Previously, the validate_request decorator did not reject an empty string, allowing the request to proceed.

• As a result, the deletion logic would run KnowledgebaseService.query(created_by=current_user.id, id=""), which could unintentionally match and delete all entries.

Type of change

• [ √] 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):

[KevinHuSh]

CI failure. Do you have any clue what happens?

[lianwenke]

@KevinHuSh
The decorator function @validate_request(...) is validating request inputs, and it specifically checks for required arguments. Your test setup is triggering the following error repeatedly:

Exception: required argument are missing or empty: asr_id;

This is because asr_id is expected in the request payload (request.json or request.form), but it's either:

• not provided,
• or is an empty string.
  Check this parameter is necessary
  

[KevinHuSh]

Appreciations!
After our evaluation, this feature is not going to be merged into main branch.