Fixes issue with file size calculation for existing logs (#8971)

* Issue arises with existing log files at startup

* Because the existing bytes are not accounted for, log rolling does not occur at the correct time

* Existing code can lead to logging being suspended indefinitely without manual intervention if thresholds are exceeded and no rolled log files can be deleted

* Corner case more evident when other data not rolled by ATS is present in the logging directory
1 file changed