Keep latest_coin_id in GUI NFT signature response so it is same as RPC response

[markelrod]

No description provided.

[ChiaMineJP]

I searched for the reason why latest_coin_id was removed in the past but found no clue.
My guess is that latest_coin_id isn't referred by the signature verification process so the author might feel it's useless. (This means latest_coin_id can be forged and amateur easily believes it's a true coin_id)

Maybe this in-verifiability is important. latest_coin_id cannot be directly verified by the signature.
Imagine there is a signature file in the internet and someone tries to verify the signature file which contains forged latest_coin_id.
If the person tries to verify the signature file with forged latest_coin_id with GUI, it might verify the sig successfully since forged latest_coin_id is nothing to do with the signature.