UTXO spent tracking

fixes #1301

frontend/src/app/services/state.service.ts

@@ -81,6 +81,7 @@ export class StateService {
   mempoolInfo$ = new ReplaySubject<MempoolInfo>(1);
   mempoolBlocks$ = new ReplaySubject<MempoolBlock[]>(1);
   txReplaced$ = new Subject<Transaction>();
+  utxoSpent$ = new Subject<null>();
   mempoolTransactions$ = new Subject<Transaction>();
   blockTransactions$ = new Subject<Transaction>();
   isLoadingWebSocket$ = new ReplaySubject<boolean>(1);

frontend/src/app/services/websocket.service.ts

@@ -251,6 +251,10 @@ export class WebsocketService {
       this.stateService.bsqPrice$.next(response['bsq-price']);
     }
 
+    if (response.utxoSpent) {
+      this.stateService.utxoSpent$.next();
+    }
+
     if (response.backendInfo) {
       this.stateService.backendInfo$.next(response.backendInfo);