fix null is not int when initCurrencyParameters

https://sentry.io/share/issue/da813434b4ba48c7b53dadaeb5d70cc1/

lib/providers/substrate_sdk.dart

@@ -537,7 +537,6 @@ class SubstrateSdk with ChangeNotifier {
         notifyListeners();
       });
 
-      await initCurrencyParameters();
       await getBalanceRatio();
 
       notifyListeners();

lib/screens/home.dart

@@ -146,8 +146,11 @@ class HomeScreen extends StatelessWidget {
                       sub.reload();
                     } else {
                       await sub.connectNode(ctx);
+                      // Currency parameters
+                      sub.initCurrencyParameters();
                     }
-                    // Indexer
+
+                    // Indexer Blockchain start
                     getBlockStart();
                   });
                   // await sub.connectNode(ctx);