Flaky Playwright test - notebook split cell #14450

[dhuebner]

What it does

• Removed flaky expectation that assumes a line element has state visible Intermittent Playwright test failures in theia-notebook-editor.test #14450
• Added logging to see the line element state if the test should fail again
• Updated Playwright to ^1.47.0 because earlier versions are not working with OS X Sequoia
• Added allure-results to .gitignore . It is produced during Playwright tests run
• Adjusted test workspace location detection, because in the latest Playwright plug-in the working directory is the workspace root. In the older version it was the playwright configuration file directory.

How to test

Tests are running automatically

Follow-ups

Further investigate failing flaky test using new logging data as it is not reproducible locally.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[planger]

Thank you! Code changes look good and the Playwright upgrade is also more than welcome. Let's observe whether this already resolves the flakiness. At least it'll give us more insights.

Thanks again!