Unexpected element. Parser was expecting element 'http://schemas.xmlsoap.org/soap/envelope/:Fault' but found 'urn:partner.soap.sforce.com:describeSObjectResponse'

Hi team,

I experience an issue when executing API calls. The client throws a following error:

`Unexpected element. Parser was expecting element 'http://schemas.xmlsoap.org/soap/envelope/:Fault' but found 'urn:partner.soap.sforce.com:describeSObjectResponse'\nCaused by: org.mule.runtime.api.connection.ConnectionException: Unexpected element. Parser was expecting element 'http://schemas.xmlsoap.org/soap/envelope/:Fault' but found 'urn:partner.soap.sforce.com:describeSObjectResponse'\nCaused by: com.sforce.ws.ConnectionException: Unexpected element. Parser was expecting element 'http://schemas.xmlsoap.org/soap/envelope/:Fault' but found 'urn:partner.soap.sforce.com:describeSObjectResponse'\n#011at com.sforce.ws.bind.TypeMapper.verifyTag(TypeMapper.java:461) ~[force-wsc-53.1.0.jar:?]\n#011at com.sforce.ws.transport.SoapConnection.createException(SoapConnection.java:203) ~[force-wsc-53.1.0.jar:?]\n#011at com.sforce.ws.transport.SoapConnection.receive(SoapConnection.java:163) ~[force-wsc-53.1.0.jar:?]\n#011at com.sforce.ws.transport.SoapConnection.send(SoapConnection.java:108) ~[force-wsc-53.1.0.jar:?]\n#011at com.sforce.soap.partner.PartnerConnection.describeSObject(PartnerConnection.java:1491) ~[force-partner-api-53.1.0.jar:?]\n#011at `

I believe all transport implementations evaluate the responses as failed when the status code >= 400:

https://github.com/forcedotcom/wsc/blob/master/src/main/java/com/sforce/ws/transport/JdkHttpTransport.java#L219

I inspected the code and came to a conclusion that this error is caused by the API returning HTTP status code >= 400, but the payload is not based on the Fault structure. Does it make sense?

Thanks for any feedback.