chore(addon/huaweipay): 变更华为支付的测试方法内容

src/addon/huaweipay/data/sdk/HuaweiPayClient.php

@@ -54,19 +54,22 @@ class HuaweiPayClient
         
         if ($type == 'private_key') {
             $header = "-----BEGIN PRIVATE KEY-----\n";
-            $footer = "\n-----END PRIVATE KEY-----";
+            $footer = "-----END PRIVATE KEY-----";
         } elseif ($type == 'public_key') {
             $header = "-----BEGIN PUBLIC KEY-----\n";
-            $footer = "\n-----END PUBLIC KEY-----";
+            $footer = "-----END PUBLIC KEY-----";
         }
         
         // 每64个字符添加一个换行
         $formattedContent = $header;
         $length = strlen($content);
+        $lines = [];
+        
         for ($i = 0; $i < $length; $i += 64) {
-            $formattedContent .= substr($content, $i, 64) . "\n";
+            $lines[] = substr($content, $i, 64);
         }
-        $formattedContent .= $footer;
+        
+        $formattedContent .= implode("\n", $lines) . $footer;
         
         return $formattedContent;
     }