Exposing Configuration Handling for Log Retention Size in LogAggregationFileController

When configuring the log aggregation retention size using yarn.nodemanager.log-aggregation.num-log-files-per-app, users may mistakenly set the value to a non-positive integer, expecting it to work without issues. However, this misconfiguration is silently corrected by defaulting to a predefined retention size of 30. This silent handling can lead to confusion as there is no system output indicating the correction, leaving users unaware of the actual configuration being applied.
 
Expected Behavior:
The system should provide log output to inform users about the applied default retention size when an invalid value is configured.
 
How-to-Fix:
We propose exposing the handling of invalid retention size values by adding logging.