Explicitly list metadata recording for DataVector<SG::AuxElement>

This is a followup of the: !55678 (merged) In detailed testing it was found that there is a warning while reading the file in AAb release. @akraszna diagnosed it to missing metadata for xAOD::BaseContainer. The suggested fix was to configure it via python interface. After playing with it seems equally good to just add this specific container in C++ default. Pending ACK from @akraszna

FI @mdyndal - who found the issue in the first place.