…gic to return the correct deletion message. Add handling for empty
arrays to ensure no errors occur during the deletion operation. Update
the test cases to verify the new logic.
### What problem does this PR solve?
fix this bug：https://github.com/infiniflow/ragflow/issues/6607
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
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Co-authored-by: wenju.li <wenju.li@deepctr.cn>
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