Refactor: Move random import to module level in autoreviewer.py

[pyob-bot]

Summary of Changes

• Moved the import random statement from the local scope within the AutoReviewer class method to the top-level imports of src/pyob/autoreviewer.py.
• Removed the redundant local import within the conditional logic.

Technical Impact

• Improves code readability and adheres to PEP 8 standards by consolidating imports at the top of the file.
• Eliminates unnecessary repeated import calls during execution, slightly optimizing the performance of the file selection logic.