Parser/RdfXml: removed xml_set_object call

Usage of xml_set_object is deprecated in PHP 8.4 in
favor of using xml_set_* functions with string method names.
Because we already do that the xml_set_object call could
be removed without any problems.

Link to the offical deprecation information for PHP 8.4:
https://wiki.php.net/rfc/deprecations_php_8_4#xml_set_object_and_xml_set_handler_with_string_method_names

lib/Parser/RdfXml.php

@@ -94,7 +94,6 @@ protected function initXMLParser()
             xml_set_element_handler($parser, [$this, 'startElementHandler'], [$this, 'endElementHandler']);
             xml_set_character_data_handler($parser, [$this, 'cdataHandler']);
             xml_set_start_namespace_decl_handler($parser, [$this, 'newNamespaceHandler']);
-            xml_set_object($parser, $this);
             $this->xmlParser = $parser;
         }
     }