XML-Inputstream should not be converted to String and back to InputStream

[rscadrde]

The commit
956bedf
made correct inputstream parsing fail:

We are using mule-module-apikit 1.7.3 and a mule server 3.7.3 running with file.encoding=Cp1252.

When posting an xml

<?xml version='1.0' encoding='UTF-8'?>
<ns0:BatteryType xmlns:ns0="http://www.ptc.com/flexplm/cunda/batterytype">
  <ns0:Id>18</ns0:Id>
  <ns0:Text>Hörgerätbatterie</ns0:Text>
</ns0:BatteryType>

message to the api kit router it fails validating the schema with:

[Fatal Error] :4:13: Invalid byte 2 of 4-byte UTF-8 sequence.
because RestXmlSchemaValidator first makes a String out of the inputstream with UTF-8 encoding:

input = IOUtils.toString((InputStream) input, muleEvent.getMessage().getEncoding());
and 7 lines later parses it with

data = loadDocument(IOUtils.toInputStream((String) input));
which uses Charset.defaultCharset() = "Cp1252"

and so the xml parser fails as the "ä" is now Cp1252 encoded but xml-header tells him UTF-8'.

Before the commit

https://github.com/mulesoft/apikit/commit/956bedf243dbfd306cfefa6f4b33712953e32455
the code of RestJsonSchemaValidator.java was correct to directly let the DocumentBuilder parse the inputstream.