napari: `multiple_viewer_widget.py` doesn't work on main branch

🐛 Bug

The examples/multiple_viewer_widget.py script is broken on the main branch.

Exactly the same issue as #5778. The fix #5796 worked but it seems that it was merged on the 0.4.18 branch and not on the main?

Sorry to bother you with that, I have a script relying on this example 😄

To Reproduce

Steps to reproduce the behavior:

1. python examples/multiple_viewer_widget.py
2. Open Sample -> napari builtins -> Cells

I have a stacktrace similar to #5778.

Expected behavior

It should open the image.

Environment

• Please copy and paste the information at napari info option in help menubar here:

napari: 0.5.0a2.dev101+g3ab9cfbb.d20230811
Platform: Windows-10-10.0.22621-SP0
Python: 3.11.4 (tags/v3.11.4:d2340ef, Jun 7 2023, 05:45:37) [MSC v.1934 64 bit (AMD64)]
Qt: 5.15.2
PyQt5: 5.15.9
NumPy: 1.25.2
SciPy: 1.11.1
Dask: 2023.8.0
VisPy: 0.13.0
magicgui: 0.7.2
superqt: unknown
in-n-out: 0.1.8
app-model: 0.2.0
npe2: 0.7.2

OpenGL:
- GL version: 4.6.0 NVIDIA 536.23
- MAX_TEXTURE_SIZE: 32768

Screens:
- screen 1: resolution 1920x1080, scale 1.0

Settings path:
- C:\Users\jeanp\AppData\Local\napari\.venv_fb2b1f9dcb189b4357857792287bfb8c719ecb7c\settings.yaml

• Any other relevant information:

Additional context