public Map<TSeriesPartitionSlot, TTimeSlotList> filterUnassignedDataPartitionSlots(
      Map<TSeriesPartitionSlot, TTimeSlotList> partitionSlots) {
    return dataPartitionTable.filterUnassignedDataPartitionSlots(partitionSlots);
  }
Only Leader use this interface. Filter unassigned DataPartitionSlots within the specific
StorageGroup.

@param partitionSlots List<TSeriesPartitionSlot>
@return Unassigned PartitionSlots
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/persistence/partition/DatabasePartitionTable.java