Sweep 'PyUtils_Parse_FileMetaData' into '22.0-mc20'
In ATLASRECTS-6757 it was requested that the changes from !49279 (merged) should also be ported to 22.0-mc20. As a necessary first step, the MetaReader must be able to return the xAOD::FileMetaData content, thus this manual sweep from a commit to master to also go into 22.0-mc20.