Remove Tx arguments from add_signatures functions

The only reason we need this argument is because we need to access
the output descriptor. We can save that one ahead of time at when
we construct the type.

swap/src/database/alice.rs

@@ -205,7 +205,7 @@ impl From<Alice> for AliceState {
                 let tx_refund = TxRefund::new(&tx_cancel, &state3.refund_address);
                 AliceState::BtcPunishable {
                     monero_wallet_restore_blockheight,
-                    tx_refund,
+                    tx_refund: Box::new(tx_refund),
                     state3: Box::new(state3),
                 }
             }