Fix: Correctly deal with new coinbase transactions for the same height

A bug was observed that now and then a Coinbase Transaction would not conclude its monitoring with this error:
`ValueNotFound(CompletedTransaction(15645503741743694020))`

This occurred when due to a small network reorg the miner would request a block for the same height. The new request would often have a different amount of fees which would mean this transaction needs to be cancelled in favour of the new transaction. However, with the transaction being cancelled the coinbase monitoring task will come around to checking the DB if the transaction is still there so it can continue to poll the base node and will get the ValueNotFound error. This is correct behaviour so should not have been logged as an error. The error case also means that the TransactionCancelled event is never fired which resulted in the console wallet UI not updating the state of that transaction which left it in the transaction list erroneous.

So this PR handles that “Error” properly and sends the event before ending the coinbase monitoring	task.

base_layer/wallet/src/output_manager_service/service.rs

@@ -663,6 +663,11 @@ where TBackend: OutputManagerBackend + 'static
         fees: MicroTari,
         block_height: u64,
     ) -> Result<Transaction, OutputManagerError> {
+        debug!(
+            target: LOG_TARGET,
+            "Building coinbase transaction for block_height {} with TxId: {}", block_height, tx_id
+        );
+
         let (spending_key, script_key) = self
             .resources
             .master_key_manager

base_layer/wallet/src/transaction_service/protocols/transaction_coinbase_monitoring_protocol.rs

@@ -121,17 +121,23 @@ where TBackend: TransactionBackend + 'static
             let completed_tx = match self.resources.db.get_completed_transaction(self.tx_id).await {
                 Ok(tx) => tx,
                 Err(e) => {
-                    error!(
+                    info!(
                         target: LOG_TARGET,
-                        "Cannot find Completed Transaction (TxId: {}) referred to by this Coinbase Monitoring \
-                         Protocol: {:?}",
-                        self.tx_id,
-                        e
+                        "Cannot find Coinbase Transaction (TxId: {}) likely due to being cancelled: {}", self.tx_id, e
                     );
-                    return Err(TransactionServiceProtocolError::new(
-                        self.tx_id,
-                        TransactionServiceError::TransactionDoesNotExistError,
-                    ));
+                    let _ = self
+                        .resources
+                        .event_publisher
+                        .send(Arc::new(TransactionEvent::TransactionCancelled(self.tx_id)))
+                        .map_err(|e| {
+                            trace!(
+                                target: LOG_TARGET,
+                                "Error sending event, usually because there are no subscribers: {:?}",
+                                e
+                            );
+                            e
+                        });
+                    return Ok(self.tx_id);
                 },
             };
             debug!(
@@ -332,9 +338,7 @@ where TBackend: TransactionBackend + 'static
                             }
                         }
                     }
-                    result = self.query_coinbase_transaction(
-                        signature.clone(), completed_tx.clone(), &mut client
-                    ).fuse() => {
+                    result = self.query_coinbase_transaction(signature.clone(), completed_tx.clone(), &mut client).fuse() => {
                         let (coinbase_kernel_found, metadata) = match result {
                             Ok(r) => r,
                             _ => (false, None),