🧹 Remove unused 'should_reject_hedged' method

[LeandroPG19]

🎯 What: The code health issue addressed was the presence of an unused method should_reject_hedged in the ewma_reward.rs file.
💡 Why: This improves maintainability and readability by removing logic that is no longer used or needed.
✅ Verification: The removal was manually verified by reading the file content. An attempt was made to run cargo check and cargo test, but was skipped due to environment restrictions (missing local dependencies and no internet access).
✨ Result: The codebase is cleaner and easier to maintain.

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PR created automatically by Jules for task 16344263677469372738 started by @LeandroPG19

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