Add helper to wait for validation interface queue to catch up

src/wallet/wallet.cpp

@@ -1292,12 +1292,7 @@ void CWallet::BlockUntilSyncedToCurrentChain() {
     // ...otherwise put a callback in the validation interface queue and wait
     // for the queue to drain enough to execute it (indicating we are caught up
     // at least with the time we entered this function).
-
-    std::promise<void> promise;
-    CallFunctionInValidationInterfaceQueue([&promise] {
-        promise.set_value();
-    });
-    promise.get_future().wait();
+    SyncWithValidationInterfaceQueue();
 }