Round up protocol fee to 1 if its 0

[smol-ninja]

Reported in Codehawk audit, a user can bypass paying the protocol fee by withdrawing in smaller amounts such that 10% of it becomes 0. For example,

• Withdraw amount: 9 tokens
• Protocol fee: 10% becomes 0.9 = 0 in solidity

Thus, as a fix, round up the protocol fee to 1 token if the following conditions are met:

1. withdraw amount > 0 AND
2. protocol fee (10% of withdraw amount ) == 0

Note: Double check that the function reverts when withdraw amount is 0 so that users do not pay a fee of 1 token when there are no tokens to withdraw.

[smol-ninja]

The same issue exists in depositViaBroker as well. Should we deduct 1 there as well in case fee rounds down to zero (the same problem exists in lockup too)? Or should we ignore it and let broker manage it on their side (since deposit amount is in their control)?

[smol-ninja]

#336 (comment)