parsers: fix tests with --features disable-validation and/or component

This disables a bunch of tests when the component feature is disabled,
because that feature changes the namespace of the <message/> element,
which causes the tests to fail.

Thanks to debacle for finding this.

parsers/ChangeLog

@@ -24,6 +24,7 @@ XXXX-YY-ZZ RELEASER <admin@example.com>
         - ibr::LegacyQuery now implements Default, allowing users to more
           easily construct it (!660)
         - jingle_rtp::Description gained a bandwidth child.
+        - Fix cargo test for the disable-validation and component features.
 
 Version 0.22.0:
 2025-10-28 pep <pep@bouah.net>