RocketNetworkWithdrawal - ETH dust lockup due to rounding errors
There's a potential `ETH` dust lockup when processing a withdrawal due to rounding errors when performing a division.\\n```\\nuint256 totalShare = rocketMinipoolManager.getMinipoolWithdrawalTotalBalance(msg.sender);\\nuint256 nodeShare = rocketMinipoolManager.getMinipoolWithdrawalNodeBalance(msg.sender);\\nuint256 userShare = totalShare.sub(nodeShare);\\n// Get withdrawal amounts based on shares\\nuint256 nodeAmount = 0;\\nuint256 userAmount = 0;\\nif (totalShare > 0) {\\n    nodeAmount = msg.value.mul(nodeShare).div(totalShare);\\n    userAmount = msg.value.mul(userShare).div(totalShare);\\n}\\n```\\n
Calculate `userAmount` as `msg.value - nodeAmount` instead. This should also save some gas.
```\\nuint256 totalShare = rocketMinipoolManager.getMinipoolWithdrawalTotalBalance(msg.sender);\\nuint256 nodeShare = rocketMinipoolManager.getMinipoolWithdrawalNodeBalance(msg.sender);\\nuint256 userShare = totalShare.sub(nodeShare);\\n// Get withdrawal amounts based on shares\\nuint256 nodeAmount = 0;\\nuint256 userAmount = 0;\\nif (totalShare > 0) {\\n    nodeAmount = msg.value.mul(nodeShare).div(totalShare);\\n    userAmount = msg.value.mul(userShare).div(totalShare);\\n}\\n```\\n