In the function below, the if block already dictates that getUnvestedAmount() == 0 manages to avoid a revert. Hence, consider refactoring the following code lines as it makes no sense adding 0 value getUnvestedAmount() of to the addend, amount:   
https://github.com/code-423n4/2023-10-ethena/blob/main/contracts/StakedUSDe.sol#L89-L99
