check_unique_controlFile too loose
I notice in !1694 (merged) that due to mistakes in previous MRs there are spurious errors, check https://gitlab.cern.ch/atlas-physics/pmg/mcjoboptions/-/jobs/20185882
This is because https://gitlab.cern.ch/atlas-physics/pmg/mcjoboptions/-/blob/master/507xxx/507035/MadGraphControl_Py8EG_2HDMa_monoH_common.py is a file rather than a link.
This means that all the future MRs that will point to this control file (and it's almost certain we'll have more) will all have the same spurious errors.
In fact this is going to happen for all files that should be links and weren't so the situation is going to become worse with time. I would therefore propose to make the test stricter, i.e. we should not allow two physical files with the same name and the same content. If the content is different then the name should be adjusted. And we should not allow the CI job to fail.