RecExConfig: Demote message levels in GetRunNumber and GetLBNumber
When it is not possible to determine the run or LB number, we agreed to return 'None'. This is to signal clients to settle with working defaults. As none of those exceptional circumstances are serious problems error messages of level DEBUG or VERBOSE seem appropriate.
Targeting 22.0-mc20 here only as by the suggestion from @emoyse. We should want these errors in master, as there they should not appear.