CellWatcher use of ZMQStream with JupyterLite

@bnmajor looking to update our docs JupyterLite itkwidgets version, and I am getting the following traceback:

```python
---------------------------------------------------------------------------
ModuleNotFoundError Traceback (most recent call last)
Cell In[3], line 1
----> 1 from itkwidgets import view
2 import imageio.v2 as imageio

File /lib/python3.10/site-packages/itkwidgets/__init__.py:12
9 from .imjoy import register_itkwasm_imjoy_codecs
10 register_itkwasm_imjoy_codecs()
---> 12 from .viewer import Viewer, view, compare_images
13 from .standalone_server import standalone_viewer
15 __all__ = [
16 "Viewer",
17 "view",
18 "compare_images",
19 "standalone_viewer",
20 ]

File /lib/python3.10/site-packages/itkwidgets/viewer.py:25
17 from ._type_aliases import Gaussians, Style, Image, PointSet, CroppingPlanes
18 from ._initialization_params import (
19 init_params_dict,
20 build_config,
(...)
23 defer_for_data_render,
24 )
---> 25 from .cell_watcher import CellWatcher
26 from .imjoy import register_itkwasm_imjoy_codecs
27 from .integrations import _detect_render_type, _get_viewer_image, _get_viewer_point_set

File /lib/python3.10/site-packages/itkwidgets/cell_watcher.py:9
7 from queue import Queue
8 from imjoy_rpc.utils import FuturePromise
----> 9 from zmq.eventloop.zmqstream import ZMQStream
11 background_tasks = set()
14 class Viewers(object):

ModuleNotFoundError: No module named 'zmq'
```

Inizia dal contesto della documentazione di JupyterLite e segui il percorso di importazione da itkwidgets/viewer.py a itkwidgets/cell_watcher.py, dove l’importazione di ZMQStream non riesce. Riproduci l’importazione segnalata in JupyterLite e verifica che la versione documentata di itkwidgets e il comportamento risultante di CellWatcher non producano più il traceback.

Scritto dal modello di indicizzazione a partire dal testo della issue.