Make Royalties non optional during creation of listing

[satyamakgec]

Context

In current implementation, Royalties are fetched and add as the sale cut within the transaction code. However, consumers of the NFTStorefrontV2 like marketplaces or third party apps have an option to not honor royalties during the creation of the listing. Now we want to make royalties mandatory.

Proposed Solution

Move the royalties from the transaction i.e sell_item.cdc to the createListing function code.

[bymi15]

This would have implications for many NFT contracts that currently have royalties defined to be received in a specific currency (e.g. FlowToken). If the listing is in a different currency (e.g. DapperUtilityCoin), then the transaction would fail if the royalty receiver specified in the NFT contract doesn't have the receiver capability.
I guess this would force NFT projects to update their contracts / wallets to use the FungibleTokenSwitchboard

[bjartek]

I mentioned this when this contract was created. Royalties should be fetched from the Metadata.Royalties that is defined in the NFT when a listing is made. This should be made in the contract and not in the transaction as that can be faked.