fix(merchant): 商户对接配置公钥取消脱敏

公钥本可公开分发，与平台公钥一致明文返回，通信密钥仍脱敏。

Co-authored-by: Cursor <cursoragent@cursor.com>

daxpay-payment/daxpay-payment-core/src/main/java/cn/daxpay/open/payment/merchant/result/config/MerchantCredentialResult.java

@@ -15,9 +15,8 @@ import lombok.experimental.Accessors;
 @Schema(title = "商户API配置结果")
 public class MerchantCredentialResult extends BaseResult {
 
-    /// 商户公钥
+    /// 商户公钥（可公开，不脱敏）
     @Schema(description = "商户公钥")
-    @SensitiveInfo(front = 12, end = 12)
     private String publicKey;
 
     /// 平台公钥