test(e2e): add snapshot test to landing page

[shootermv]

Summary of changes

learned recently about interesting feature of playwright tool - the snapshot tests.
snapshot tests means - it should compare the screenshot done in the past with screenshot after current change visually

Checklist

• I have read and followed the contribution guidelines.
• I have read through the Code of Conduct and agree to abide by the rules.
• This PR is for one of the available issues and is not a PR for an issue already assigned to someone else.
• My PR title has a short descriptive name so the maintainers can get an idea of what the PR is about.
• I have provided a summary of my changes.

closes #XXXXX

[huyenltnguyen]

Thank you for the PR.

Screenshot testing is definitely useful for visual regression testing. However, the Developer Quiz project is quite small and simple, and we want to allow some flexibility in visual display (being able to adjust the UI without too much friction). The additional tooling also comes with maintenance cost, and given the scale of the project, we decided to not proceed with this change.