Delrifai/#412 verify account starts with @

1. Validated that account starts with @ else show the error page
2. Validated if the account starts with @, it is also not empty, and there is a username after it
3. Performed Sanity check on balance history and main account page to make sure all is working as expected

Changes applied for balanceHistory/@bkocktrades(balance history) and @blocktrades (main account)

pages/balanceHistory/[accountName].tsx

@@ -178,7 +178,7 @@ export default function BalanceHistory() {
    ? router.query.accountName[0] // If it's an array, get the first element
    : router.query.accountName; // Otherwise, treat it as a string directly
 
-  if(routeAccountName  && !routeAccountName.startsWith("@") || !accountNameFromRoute) 
+  if(routeAccountName  && !routeAccountName.startsWith("@"))
   {
     return <ErrorPage />;
   }