node: Use json_node_unref for the JsonNode autoptr cleanup
node: Use json_node_unref for the JsonNode autoptr cleanup

json_node_unref was added after the autoptr macros were written.

This fixes an assertion failure if using autoptr and json_node_ref.

frida/json-glib,frida/json-glib,GNOME/json-glib,GNOME/json-glib