UI Tests check is failing on CI

[jtpio]

Opening a new issue since the check is failing on the latest commit on master: 1c08f9f

Opening the report shows some differences with the UI elements:

Not sure if this was introduced in a previous PR, but probably updating the reference snapshots should help fix it.

[jtpio]

Also the UI Tests setup could be updated to use a more recent @jupyterlab/galata based on Playwright: https://github.com/jupyterlab/jupyterlab/tree/master/galata

For example:

• https://github.com/voila-dashboards/voila/tree/main/ui-tests
• https://github.com/jupyter-widgets/ipyleaflet/tree/master/ui-tests

[jtpio]

Upgrading to the newer setup would also allow for integrations like automated snapshots updates with a bot: https://github.com/jupyterlab/maintainer-tools#update-snapshots

[maartenbreddels]

Partially fixed in #424
(not yet upgraded, will keep that in mind!)