Workflow failure when updating reference snapshots

The workflow to update reference Playwright snapshots often fails, and needs to be restarted manually for the update to be completed: https://github.com/jupyter/notebook/blob/main/.github/workflows/playwright-update.yml

It sometimes fails because of the UI test flakyness (a different issue).

And sometimes because of the following error:

https://github.com/jupyter/notebook/actions/runs/9059110076/job/24886021429


```
Run actions/upload-artifact@v4
With the provided path, there will be 3 files uploaded
Artifact name is valid!
Root directory input is valid!
Error: Failed to CreateArtifact: Received non-retryable error: Failed request: (409) Conflict: an artifact with this name already exists on the workflow run
```

Start with .github/workflows/playwright-update.yml and inspect the snapshot update workflow around actions/upload-artifact@v4. Review the linked failed workflow run to reproduce or understand the artifact conflict, while keeping the separate UI test flakiness issue distinct. Done means the reference snapshot update workflow completes without requiring a manual restart.

Written by the indexing model from the issue text.