Fixed small bug when incrementing counter in AccountManagerCallback

Author: Bluesir9

app/src/main/java/fr/free/nrw/commons/CommonsApplication.java

@@ -223,7 +223,7 @@ int getIndex() {
 
             @Override
             public void run(AccountManagerFuture<Boolean> accountManagerFuture) {
-                setIndex(index++);
+                setIndex(getIndex() + 1);
 
                 try {
                     if (accountManagerFuture != null) {