Fix amount calculation for tracked onchain payments

We recently started tracking onchain payments in the store. It turns out
the calculated amount was slightly off as in the outbound case it would
include the paid fees. Here, we fix this minor bug.

Author: tnull

src/wallet/mod.rs

@@ -187,14 +187,21 @@ where
 			// here to determine the `PaymentKind`, but that's not really satisfactory, so
 			// we're punting on it until we can come up with a better solution.
 			let kind = crate::payment::PaymentKind::Onchain { txid, status: confirmation_status };
+			let fee = locked_wallet.calculate_fee(&wtx.tx_node.tx).unwrap_or(Amount::ZERO);
 			let (sent, received) = locked_wallet.sent_and_received(&wtx.tx_node.tx);
 			let (direction, amount_msat) = if sent > received {
 				let direction = PaymentDirection::Outbound;
-				let amount_msat = Some(sent.to_sat().saturating_sub(received.to_sat()) * 1000);
+				let amount_msat = Some(
+					sent.to_sat().saturating_sub(fee.to_sat()).saturating_sub(received.to_sat())
+						* 1000,
+				);
 				(direction, amount_msat)
 			} else {
 				let direction = PaymentDirection::Inbound;
-				let amount_msat = Some(received.to_sat().saturating_sub(sent.to_sat()) * 1000);
+				let amount_msat = Some(
+					received.to_sat().saturating_sub(sent.to_sat().saturating_sub(fee.to_sat()))
+						* 1000,
+				);
 				(direction, amount_msat)
 			};