Make faucet contract upgradable

We're having faucet issues, and adding more possible callers to the [faucet contract](https://github.com/recallnet/contracts/blob/main/src/token/Faucet.sol) is a potential fix via https://github.com/recallnet/contracts/pull/96. However, our contract isn't upgradable, so we have no way to see if this fix would resolve the issue.