chore(docs): remove redirect to landing page & set latest alias to main

[danceratopz]

🗒️ Description

This PR makes two changes with regards to (unrelated) redirects:

1. It removes this redirect to the online docs' landing page:
   • https://ethereum.github.io/execution-spec-tests/main -> https://ethereum.github.io/execution-spec-tests/main/getting_started/overview/
     This was introduced to feat(docs): reorganize top-level menus in online docs #929 with the aim of reducing the amount of headers within the top-level menu bar. The redirect is ugly though and is poor nav ux. As a solution this PR removes it and simply adds a dedicated top-level "Home" entry where this landing page lives.
2. "remove update of default doc version to latest tag". It stops updating the "latest" version of the docs the last pushed tag (in .github/workflows/docs_tags.yaml). E.g., the default version of the docs will no longer redirect to vX.Y.Z, e.g., this will not happen:
   • https://ethereum.github.io/execution-spec-tests -> https://ethereum.github.io/execution-spec-tests/vX.Y.Z/
     This also required this one-time mike command to update the latest alias to point to main

   uv run mike deploy --update-aliases --rebase --push --remote origin main latest
   

🔗 Related Issues

#929

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.

[spencer-tb]

Thanks! LGTM

[spencer-tb]

I'm not sure how to but can we update the docs link on the EEST main page to point to:
https://ethereum.github.io/execution-spec-tests/main?

Currently its https://ethereum.github.io/execution-spec-tests/ which points to https://ethereum.github.io/execution-spec-tests/latest -> https://ethereum.github.io/execution-spec-tests/v3.0.0!

What do you think?

[danceratopz]

I'm not sure how to but can we update the docs link on the EEST main page to point to: https://ethereum.github.io/execution-spec-tests/main?

Currently its https://ethereum.github.io/execution-spec-tests/ which points to https://ethereum.github.io/execution-spec-tests/latest -> https://ethereum.github.io/execution-spec-tests/v3.0.0!

What do you think?

Done in 6e341c9 - see description for details and the mike command 😆