Update gitlab-workspaces-tools image to 4.0.0

What does this MR do and why?

Update the gitlab-workspaces-tools images to be used in Workspaces. This images

• Updates the version of VS Code fork to 1.93.1
• Bundle the GitLab theme extension giving users the ability to use these themes which makes it consistent with Web IDE themes.

References

Please include cross links to any resources that are relevant to this MR. This will give reviewers and future readers helpful context to give an efficient review of the changes introduced.

• Issue: Use VSCode Fork 1.93.1 in Workspaces (gitlab-org/workspaces/gitlab-workspaces-tools#10 - closed)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Screenshot of the version of VS Code fork

Screen recording of selecting the GitLab themese

Screen_Recording_2025-01-10_at_3.31.16_PM

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.