The supernumerary flights are part of the learning process to observe and get used to the speed of events before undergoing simulator training.
The other major factor is that there are mandatory call-outs on final approaches that a co-pilot has to give. The untrained pilot will not be in a position to do that, nor will the person be able to spot any deviations from a safe flight path.
(From the
linked livemint article - my bolding)
.. so it seems this was a supernumerary flight
before endorsement training.