task: #3621399 Update @vardot/varbase-e2e to ^2.0.4

Moves the Varbase Starter functional testing harness onto ^2.0.4, and makes the committed lock install it.

Issue: https://www.drupal.org/project/varbase_starter/issues/3621399

What changed

• package.json: "@vardot/varbase-e2e" from "^2" to "^2.0.4".
• This project commits no lock file, so that one line is the whole diff.

Nothing else. No step definition, feature file or selector is touched.

Why

The constraint said ^2, which does not state the floor the suite now needs. Any environment that installed before 2.0.4 stays on the old steps.

@vardot/varbase-e2e 2.0.4 adds 17 built-in steps and fixes one. What this project gains:

• Access assertions, so a scenario can state what a role may and may not reach.
• Page title assertions.
• An added HTTP status code phrasing.
• A fix to the existing HTTP status step. It used to re-request the URL outside the browser, losing the session cookies and following redirects, so it asserted a different request than the one under test. It is now session aware.

Test notes

The harness installs at 2.0.4, and the dry run is clean across all 281 scenarios and 1921 steps — nothing ambiguous, nothing undefined. That is the evidence that none of the new 2.0.4 steps collide with anything this project defines locally.

The browser suites were not run: this change alters no step and no scenario.

AI-Generated: Yes

Checkpoints:

• File an issue
• Addition/Change/Update/Fix
• Testing to ensure no regression
• Automated unit testing coverage
• Automated functional testing coverage
• UX/UI designer responsibilities
• Readability
• Accessibility
• Performance
• Security
• Developer Documentation
• User Guide Documentation
• Reviewed by human
• Code review by maintainers
• Full testing and approval
• Credit contributors
• Review with the product owner
• Release notes snippet
• Release