Add Collection to the data_hash keccak::hashv

[c4b4d4]

Can we change this to take the "collection" in consideration when second-hashing the metadata?

Right now, to verify the collection we need to pass the entire Metadata to the instruction, which reduces composability because it increases the Transaction Size by A LOT.

// @dev: seller_fee_basis points is encoded twice so that it can be passed to marketplace
// instructions, without passing the entire, un-hashed MetadataArgs struct
let metadata_args_hash = keccak::hashv(&[message.try_to_vec()?.as_slice()]);
let data_hash = keccak::hashv(&[
    &metadata_args_hash.to_bytes(),
    &message.seller_fee_basis_points.to_le_bytes(),
]);

mpl-bubblegum/programs/bubblegum/program/src/processor/mint.rs

Line 113 in cea5f00

let data_hash = keccak::hashv(&[