Fix python imports when built without SIO support

[tmadlener]

BEGINRELEASENOTES

• Fix bugs in python imports when podio is built without SIO support. Fixes New python import structure does not work if SIO backend is not built #489

ENDRELEASENOTES

@kjvbrt do you want to give this a go?

[kjvbrt]

Works for AlmaLinux9 now :)

16:53:49 [jsmiesko@fcc-ironic-03 podio (fix-py-import-no-sio =)]$ podio-dump output_fullCalo_SimAndDigi.root 
/home/jsmiesko/podio/install/python/podio/EventStore.py:4: FutureWarning: The EventStore based I/O model is deprecated and will be removed. Switch to the Frame based model.
  warnings.warn("The EventStore based I/O model is deprecated and will be removed. Switch to the Frame based model.",
input file: output_fullCalo_SimAndDigi.root

datamodel model definitions stored in this file: edm4hep

Frame categories in this file:
Name                 Entries   
-------------------------------
metadata             1         
events               2         
configuration_metadata 1         

#################################### events 0 ####################################
Collections:
Name                       ValueType                  Size  ID
-------------------------  -----------------------  ------  --------
CaloClusters               edm4hep::Cluster              1  706db4eb
CorrectedCaloClusters      edm4hep::Cluster              1  38fde31e
ECalBarrelCells            edm4hep::CalorimeterHit      68  269139f6
ECalBarrelPositionedCells  edm4hep::CalorimeterHit      68  65cb8aec
ECalEndcapCells            edm4hep::CalorimeterHit       0  55d4e559
GenParticles               edm4hep::MCParticle           1  0bcf5f90

Parameters:
Name    Type    Elements
------  ------  ----------

[tmadlener]

Thanks for checking.