Remove min_interval_seconds from plugin workers; vacuum default to 17m (#8790)

remove min_interval_seconds from plugin workers and default vacuum interval to 17m

The worker-level min_interval_seconds was redundant with the admin-side
DetectionIntervalSeconds, complicating scheduling logic. Remove it from
vacuum, volume_balance, erasure_coding, and ec_balance handlers.

Also change the vacuum default DetectionIntervalSeconds from 2 hours to
17 minutes to match the previous default behavior.

weed/worker/tasks/vacuum/detection.go

@@ -105,7 +105,7 @@ func createVacuumTaskParams(task *types.TaskDetectionResult, metric *types.Volum
 
 	if vacuumConfig != nil {
 		garbageThreshold = vacuumConfig.GarbageThreshold
-		// Note: VacuumTaskConfig has GarbageThreshold, MinVolumeAgeHours, MinIntervalSeconds
+		// Note: VacuumTaskConfig has GarbageThreshold, MinVolumeAgeHours
 		// Other fields like VerifyChecksum, BatchSize, WorkingDir would need to be added
 		// to the protobuf definition if they should be configurable
 	}