[W-14651311] add attribute to xml property when has example

[alexpmule]

Description:

We should show example XML to OAS Rest API's

Steps to reproduce:

Build or view in Desging center OAS API Spec attached
Go to books/recommendations
Go to POST
In the Panel Documentation not show payload example

Current Behaviour:

Not show example payload

Expected Behaviour:

<?xml version="1.0" encoding="UTF-8"?>
<Book LocationAttr1="Sample1" LocationRefs3="SampleId" LocationAttr="string" LocationRefs="SampleId">
  <author_name></author_name>
  <book_title>Rob</book_title>
  <pages>200</pages>
  <genre></genre>
  <id></id>
</Book>

result

spec

00388196-test.zip