[Python] ipywidgets not displaying in JupyterLab & Jupyter Notebook: 'Error displaying widget'

I'm trying to use ipywidgets in JupyterLab, but I'm getting the error: Error displaying widget

Here's a minimal example that reproduces the issue:

import ipywidgets as widgets
from IPython.display import display
slider = widgets.IntSlider(min=0, max=100)
display(slider)


What I've checked so far:

1. jupyter --version:

IPython : 8.30.0
ipykernel : 6.29.5
ipywidgets : 7.7.2
jupyter_client : 8.6.3
jupyter_core : 5.7.2
jupyter_server : 2.14.1
jupyterlab : 4.3.4
nbclient : 0.8.0
nbconvert : 7.16.4
nbformat : 5.10.4
notebook : 7.3.2
qtconsole : 5.6.1
traitlets : 5.14.3

1. jupyter labextension list :

JupyterLab v4.3.4
JupyterLab v4.3.4
/home/username/.conda/envs/test_venv/share/jupyter/labextensions
jupyterlab-plotly v5.24.1 enabled X
@lckr/jupyterlab_variableinspector v3.1.0 enabled OK (python, lckr_jupyterlab_variableinspector)
@pyviz/jupyterlab_pyviz v3.0.2 enabled OK
@jupyter-notebook/lab-extension v7.3.2 enabled OK
@jupyter-widgets/jupyterlab-manager v3.0.0 enabled X (python, jupyterlab_widgets)


The following extensions may be outdated or specify dependencies that are incompatible with the current version of jupyterlab:
jupyterlab-plotly
@jupyter-widgets/jupyterlab-manager

If you are a user, check if an update is available for these packages.
If you are a developer, re-run with `--verbose` flag for more details.

Other labextensions (built into JupyterLab)
app dir: /home/username/.conda/envs/test_venv/share/jupyter/lab
@jupyterlab/plotly-extension v1.0.0 enabled X

The following extensions may be outdated or specify dependencies that are incompatible with the current version of jupyterlab:
@jupyterlab/plotly-extension

If you are a user, check if an update is available for these packages.
If you are a developer, re-run with `--verbose` flag for more details.


How can I fix this issue and get ipywidgets to display properly in JupyterLab and Jupyter Notebook? Do I need to reinstall or update specific extensions?

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