Increasing inputFilesPerJob

Description of bug

Previously, with evgenConfig.inputFilesPerJob = 5, there was a very high failure rate in both mc23a and mc23c jobs.

Changes introduced

Now, evgenConfig.inputFilesPerJob = 6

Tests

Full description of the failure in the production jobs can be found in this JIRA https://its.cern.ch/jira/browse/ATLMCPROD-10823

Issues resolved

Closes #