"Segmentation FCan't pickle local object 'SemSegRandomSampler.get_point_sampler.<locals>._random_centered_gen'ault while training RandLANet on S3DIS")

### Checklist

- [X] I have searched for [similar issues](https://github.com/isl-org/Open3D-ML/issues).
- [X] I have tested with the [latest development wheel](http://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](http://www.open3d.org/docs/release/) and the [latest documentation](http://www.open3d.org/docs/latest/) (for `master` branch).

### Describe the issue

When I am trying to run "python scripts/run_pipeline.py torch -c ml3d/configs/randlanet_semantickitti.yml --dataset.dataset_path ../dataset/SemanticKitti --pipeline SemanticSegmentation --dataset.use_cache True --num_workers 0" I am getting "ForkingPickler(file, protocol).dump(obj)
AttributeError: Can't pickle local object 'SemSegRandomSampler.get_point_sampler.._random_centered_gen'
[W CudaIPCTypes.cpp:15] Producer process has been terminated before all shared CUDA tensors released. See Note [Sharing CUDA tensors]"

### Steps to reproduce the bug

```python
$ python scripts/run_pipeline.py torch -c ml3d/configs/randlanet_semantickitti.yml --dataset.dataset_path ../dataset/SemanticKitti --pipeline SemanticSegmentation --dataset.use_cache True --num_workers 0
```

### Error message

regular arguments
backend: gloo
batch_size: null
cfg_dataset: null
cfg_file: ml3d/configs/randlanet_semantickitti.yml
cfg_model: null
cfg_pipeline: null
ckpt_path: null
dataset: null
dataset_path: null
device: cuda
device_ids:
- '0'
framework: torch
host: localhost
main_log_dir: null
max_epochs: null
mode: null
model: null
pipeline: SemanticSegmentation
port: '12355'
seed: 0
split: train

extra arguments
dataset.dataset_path: /home/sazid/Open3D-ML/scripts/dataset/SemanticKitti
dataset.use_cache: 'True'
num_workers: '0'

INFO - 2022-10-20 13:25:56,253 - semantic_segmentation - DEVICE : cuda
INFO - 2022-10-20 13:25:56,253 - semantic_segmentation - Logging in file : ./logs/RandLANet_SemanticKITTI_torch/log_train_2022-10-20_13:25:56.txt
INFO - 2022-10-20 13:25:56,286 - semantickitti - Found 19130 pointclouds for train
INFO - 2022-10-20 13:25:57,425 - semantickitti - Found 4071 pointclouds for validation
INFO - 2022-10-20 13:25:57,677 - semantic_segmentation - Initializing from scratch.
INFO - 2022-10-20 13:25:57,678 - semantic_segmentation - Writing summary in train_log/00008_RandLANet_SemanticKITTI_torch.
INFO - 2022-10-20 13:25:57,678 - semantic_segmentation - Started training
INFO - 2022-10-20 13:25:57,679 - semantic_segmentation - === EPOCH 0/100 ===
training: 0%| | 0/4783 [00:00
sys.exit(main())
File "/home/sazid/Open3D-ML/scripts/run_pipeline.py", line 179, in main
pipeline.run_train()
File "/home/sazid/miniconda3/envs/test/lib/python3.10/site-packages/open3d/_ml3d/torch/pipelines/semantic_segmentation.py", line 406, in run_train
for step, inputs in enumerate(tqdm(train_loader, desc='training')):
File "/home/sazid/miniconda3/envs/test/lib/python3.10/site-packages/tqdm/std.py", line 1195, in __iter__
for obj in iterable:
File "/home/sazid/miniconda3/envs/test/lib/python3.10/site-packages/torch/utils/data/dataloader.py", line 444, in __iter__
return self._get_iterator()
File "/home/sazid/miniconda3/envs/test/lib/python3.10/site-packages/torch/utils/data/dataloader.py", line 390, in _get_iterator
return _MultiProcessingDataLoaderIter(self)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/site-packages/torch/utils/data/dataloader.py", line 1077, in __init__
w.start()
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/process.py", line 121, in start
self._popen = self._Popen(self)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/context.py", line 224, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/context.py", line 300, in _Popen
return Popen(process_obj)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/popen_forkserver.py", line 35, in __init__
super().__init__(process_obj)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/popen_fork.py", line 19, in __init__
self._launch(process_obj)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/popen_forkserver.py", line 47, in _launch
reduction.dump(process_obj, buf)
File "/home/sazid/miniconda3/envs/test/lib/python3.10/multiprocessing/reduction.py", line 60, in dump
ForkingPickler(file, protocol).dump(obj)
AttributeError: Can't pickle local object 'SemSegRandomSampler.get_point_sampler.._random_centered_gen'
[W CudaIPCTypes.cpp:15] Producer process has been terminated before all shared CUDA tensors released. See Note [Sharing CUDA tensors]

### Expected behavior

_No response_

### Open3D, Python and System information

```markdown
- Operating system: Pop OS 22.04
- Python version: Python 3.10
- Open3D version: 0.16.0
- System type: x86
- Is this remote workstation?: no
- How did you install Open3D?: pip
```

### Additional information

_No response_