Handle donation attack of Lido withdrawal NFTs

[naddison36]

Changes

• Someone can temporarily freeze withdrawals from the Lido queue by transferring a Lido withdrawal NFT and then claiming it via the Lido ARM. As the withdrawal request was not done through the Lido ARM, the lidoWithdrawalQueue amount will be smaller than the ETH received by the claim process. This will cause and underflow if all withdrawal requests are claimed.
• The avoid underflows, lidoWithdrawalQueue is set to zero if its going to underflow.

[naddison36]

Closing for an alternative approach of storing the withdrawal request amount so any Lido mass slashing events can be better socialised to LP holders.