Fix voucher random code generation

src/routes/admin/api/transactions.js

@@ -115,7 +115,7 @@ function generateRandomString(forbidden=new Set(), length=6, chars="ABCDEFGHIJKL
 	for(let i = 0; i < length; i++){
 		result += chars.charAt(Math.floor(Math.random() * chars.length));
 	}
-	if(forbidden.has(result)) return generateRandomString(length, chars, forbidden);
+	if(forbidden.has(result)) return generateRandomString(forbidden, length, chars);
 	else return result;
 }
 export async function bulkCreateVouchers(amount, value, expiresAt){