Use new BTC change address on RGB transfer

[cryptoquick]

In this transaction we're sending the coin that's used to pay for the dust output and fees is sent back to the address:

https://mempool.space/testnet/tx/19e844a8a3d540438700f710bec6ad589bac8c0fea5266aeba7040fa7744ef5a

Notice that the address is reused. We should avoid address reuse, and instead, we should send the change to an unused BTC change wallet address.