Update comment once we learn how CosmWasm message ordering works

[0xekez]

i think the CosmWasm documentation and code are a little self-contradictory about message ordering. this doesn't impact the functionality of this contract, but we'll need to update a comment in the code depending on the outcome of this:

https://github.com/CosmWasm/cosmwasm/issues/1514

the comment:

https://github.com/public-awesome/ics721/blob/52852e07446c91983a91495e85103370f49814a7/contracts/cw-ics721-bridge/src/contract.rs#L356-L361