Another fix for nevents check for MG

Description of bug

• nevents check in MG was comparing an int with a float resulting in a wrong behaviour
• the error message printed in this case was confusing since I forgot to change the prinout when I fixed this in !443 (merged)

Changes introduced

• convert everything to int when checking nevents for MG
• fix mistake in printout

Tests

Using the output from this pipeline: https://gitlab.cern.ch/atlas-physics/pmg/mcjoboptions/-/jobs/8411228

Before fix

ERROR: Increase nevents to be generated in MG from 110 to 11000

The bug here is that

• it should have succeeded since we need 110 events
• it prints out 11000 (1.1nEventsPerJob) instead of 110 (1.1nEventsRequested) (where the latter is actually used in the check that triggers the error)

After fix

The above test succeeds.

Also if I change

20:18:36 Py:MadGraphUtils     INFO "nevents" = 110.0

to

20:18:36 Py:MadGraphUtils     INFO "nevents" = 100.0

in the log it prints out

ERROR: Increase nevents to be generated in MG from 100 to 110

so it seems to be correct now.

Issues resolved

Closes #