Fix, allow rescan if other crypto nodes are not synched

BTCPayServer/Controllers/WalletsController.cs

@@ -279,7 +279,7 @@ namespace BTCPayServer.Controllers
                 return NotFound();
 
             var vm = new RescanWalletModel();
-            vm.IsFullySync = _dashboard.IsFullySynched();
+            vm.IsFullySync = _dashboard.IsFullySynched(walletId.CryptoCode, out var unused);
             // We need to ensure it is segwit, 
             // because hardware wallet support need the parent transactions to sign, which NBXplorer don't have. (Nor does a pruned node)
             vm.IsSegwit = paymentMethod.DerivationStrategyBase.IsSegwit();