Fix unauthenticated get default currency.

app/Support/Amount.php

@@ -160,11 +160,13 @@ class Amount
 
     public function getDefaultCurrency(): TransactionCurrency
     {
+        if(auth()->check()) {
             /** @var User $user */
             $user = auth()->user();
-
             return $this->getDefaultCurrencyByUserGroup($user->userGroup);
         }
+        return $this->getSystemCurrency();
+    }
 
     public function getDefaultCurrencyByUserGroup(UserGroup $userGroup): TransactionCurrency
     {