fix(response_optimizer): handle poisoned mutex in feedback_stats

[ashnaaseth2325-oss]

Summary

This PR prevents runtime panics in ResponseOptimizerTool caused by poisoned mutex locks by replacing .lock().unwrap() with safe recovery.

Changes

• Replace .lock().unwrap() with .unwrap_or_else(|e| e.into_inner())
• Applied in update_feedback_stats and execute paths

How you Tested

• cargo check -p mofa-plugins
• cargo test -p mofa-plugins (23/23 passed)

[ashnaaseth2325-oss]

Hello @LuigiGonnella @mugiwaraluffy56
This PR fixes a potential panic by handling poisoned mutex safely instead of using .unwrap().
Tested with cargo check and cargo test (all passing).
Thanks!