Refactor: Improve pending proposal outcome handling in AutoReviewer

[pyob-bot]

Summary of Changes

• Renamed the proposals_handled variable to proposals_outcome to better reflect the new, more granular return type from _handle_pending_proposals.
• Updated the conditional logic to explicitly check for proposals_outcome == "SKIPPED" to halt the pipeline iteration.
• Ensured changes_made is only set to True when proposals are explicitly APPLIED.
• Added a clarifying comment to explain that when proposals are DELETED, changes_made remains False, allowing the pipeline to proceed with a fresh scan.

Technical Impact

• Increased Clarity: The change makes the flow of control after handling pending proposals more explicit and easier to understand by using a descriptive outcome string instead of a boolean.
• Improved Logic for Deleted Proposals: Previously, if proposals were deleted, the changes_made flag would not be set, but the pipeline would continue. This change explicitly clarifies that deleting proposals allows the scan to proceed without marking changes_made as True, which is appropriate as no new changes were applied from pending proposals.
• Maintainability: The more explicit outcome handling improves the maintainability of the AutoReviewer class by clearly distinguishing between skipped, applied, and deleted proposal states.
• No change in behavior for "SKIPPED" or "APPLIED" scenarios. The behavior for "DELETED" is now explicitly handled and clarified.