Refactor balance handling in Wallet model

- Simplified the conversion of the available balance to a string by removing the conditional check for string type.
- Ensured consistent type casting for better clarity and maintainability.

Author: rez1dent3

src/Models/Wallet.php

@@ -144,7 +144,7 @@ public function refreshBalance(): bool
             /** @var float|int|non-empty-string $balanceRaw */
             $balanceRaw = $this->getAvailableBalanceAttribute();
             /** @var non-empty-string $balance */
-            $balance = is_string($balanceRaw) ? $balanceRaw : (string) $balanceRaw;
+            $balance = (string) $balanceRaw;
             if (app(MathServiceInterface::class)->compare($whatIs, $balance) === 0) {
                 return true;
             }