Autotests: adapt test data to Qt no longer emitting ":" before base attribute

In older Qt versions QDomElement has been streaming itself to QTextStream
with the "base" attribute name prefixed by ":".

Qt 6.5.1 at least no longer does that, so in the test reference data update
the strings and respectively affected hash values.

See ElementWrapper::childNodesAsXML(const QDomElement &) for the code
affected by the change and yielding a different string.