In JupyterLab 4.02, ipywidgets throws error in console on saving widget state.

[kolibril13]

In JupyterLab 4.02 with the setting "save widget state automatically" enabled, I get the following message in the console when saving the notebook (even if there's no widget present in the notebook):

TypeError: this._context.model.metadata.set is not a function at f._saveState

The error does not come when the "save widget state automatically" setting is not activated.

here is the environment that I've used:

python3.11 -m venv .venv
source .venv/bin/activate   
pip install jupyterlab   
pip install ipywidgets 
python -m jupyterlab

I've also tested this in an older version (pip install jupyterlab==3.6), and there it worked fine without the error.

Context: I've observed this error while working on this issue widgetti/ipyreact#40

[martinRenou]

Thanks for opening an issue. This should be fixed by #3752