fix: Replace tx.origin with msg.sender for fee refunds in FeeManagerBase

[sashaodessa]

Description

• Summary: Eliminate the tx.origin anti-pattern in the fee refund path to ensure correct and predictable refunds.
• Change: Refund excess ETH to msg.sender instead of tx.origin in FeeManagerBase.collectFee;
• Impact: Improves compatibility with contract callers, multisigs, and account abstraction; no behavioral change for direct EOA calls.