Display selected device group in Scheduled Discovery Task Management view

When a scheduled Discovery or Benchmark task is configured with device scope set to a Device Group, the Task Management screen currently displays 'N/A' in the device scope column instead of the selected group name, leaving administrators unable to confirm which scope was actually applied to the task. This enhancement would update the Task Management view to display the actual Device Group name (or other selected scope type) for scheduled Discovery and Benchmark tasks. Providing this visibility would allow administrators to verify scheduled task configurations are correct without needing to reopen or re-edit the task definition, reducing uncertainty and troubleshooting effort for scheduled discovery operations.