chore(redteam): enhance metadata tracking for iterative provider

[mldangelo]

Summary of Changes

This update enhances the metadata tracking for the iterative provider in the Redteam module.

Key Modifications

• Introduced previousOutputs array to store prompt, output, score, and topic relevance for each iteration.
• Added finalIteration to track the last iteration executed.
• Updated the metadata object to include finalIteration, highestScore, previousOutputs, and redteamFinalPrompt.

Implementation Details

• The previousOutputs array is populated during each iteration with the current iteration's data.
• The finalIteration variable is set when a high-score condition is met, indicating the iteration at which the loop terminated.
• Metadata returned now includes detailed information about the iteration process for better traceability and debugging.

Testing Considerations

• Ensure the updated metadata structure is correctly populated and returned.
• Validate that the previousOutputs array accurately reflects all iterations.
• Confirm the finalIteration value corresponds to the correct iteration.

Breaking Changes

• None expected, as the changes are additive to the metadata structure.