fix：api exception

Author: volc-sdk-team

volcengine-java-sdk-core/src/main/java/com/volcengine/ApiException.java

@@ -103,6 +103,13 @@ public String getResponseBody() {
         return responseBody;
     }
 
+    public ResponseMetadata getResponseMetadata() {
+        return responseMetadata;
+    }
+
+    public void setResponseMetadata(ResponseMetadata responseMetadata) {
+        this.responseMetadata = responseMetadata;
+    }
 
     @Override
     public String toString() {