[LST][Security]: current vault does not work with fee-on-transfer tokens

[adu-web3]

Description

Though we only create vault for whitelisted tokens, it's better we specify in the comment that the whitelisted token should not be fee-on-transfer token. For fee-on-transfer token, if A transfers X amount of token to B, the transfer would burn part of token as fee Y, so the vault would receive less amount of token(X-Y) then expected when user deposits, so we should make this clear in code comments or doc.