interfaces: register a ``IXmlrpcChecker` for Zope 5.8.2 compatibility (nexedi/erp5!1751).

Since Zope commit 020685087 (`Allow ZPublisher to handle a query string together
with a request body (#1124)`, 2023-05-15) Zope tries to process all XML HTTP
requests as XML-RPC and we need to tell that these SOAP requests are not XML-RPC.