ETHx Smart Contract Upgrade

Based on community feedback post-launch and our commitment to improving the ETHx staking experience, we are proposing a smart contract upgrade with two key changes:

A. Enhanced Node Operator Withdrawal Reward Address Security Node Operators can now change their Reward Address exclusively from the existing reward address, improving security.

B. Onchain Referral Tracking To establish transparent referral tracking for the ETHx referral program, we are adding two new functions to the ETHx smart contract to allow deposits and withdrawals with a referral_id for tracking.