fix(config): implement robust project root detection for env.yaml (#1674)

[Khushi-Chaudhary04]

🗒️ Description

The function get_project_root() in packages/testing/src/execution_testing/config/env.py previously relied only on traversing the directory tree to find the .git directory. This caused failures when running the eest make env command in environments where Git metadata is absent (e.g., in distributed Python packages or CI environments).

This PR introduces two fallback mechanisms to ensure the project root (where env.yaml is placed) can always be determined:

1. It checks for the high-priority EEST_PROJECT_ROOT environment variable.
2. If the variable is unset and .git is not found, it falls back to the Current Working Directory (Path.cwd()) and emits a warning.

🔗 Related Issues or PRs

Fixes #1674

✅ Checklist

• All: Ran fast tox checks to avoid unnecessary CI fails, see also Code Standards and Enabling Pre-commit Checks:
      console     uvx tox -e static    
• All: PR title adheres to the [repo standard](https://eest.ethereum.org/main/getting_started/contributing/?h=contri#commit-messages-issue-and-pr-titles) - it will be used as the squash commit message and should start type(scope):.
• All: Considered adding an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• All: Set appropriate labels for the changes (only maintainers can apply labels).
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.
• Tests: For PRs implementing a missed test case, update the post-mortem document to add an entry the list.
• Ported Tests: All converted JSON/YML tests from ethereum/tests or tests/static have been assigned @ported_from marker.

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[SamWilsn]

Personally, I'd raise an exception rather than fallback to the current directory. It's too easy to create random env.yaml.

[Khushi-Chaudhary04]

Hey @SamWilsn, thanks for the review!

That's a valid concern about the security risk. I went with the CWD fallback because of the user's intent: they are explicitly running eest make env.

For anyone using a packaged/non-git install, if we raise an exception, that command is effectively broken unless they know to manually set EEST_PROJECT_ROOT. The CWD fallback makes make env usable out-of-the-box and ensures the file is created where they ran the command, fulfilling their request.

If the team (cc @danceratopz) prefers strict compliance over out-of-the-box usability for the make env command, I'm happy to switch to raising an exception instead. Just let me know the policy direction!

[SamWilsn]

More a question for @danceratopz , but instead of configuring this through an environment variable, would it make sense to remove the ENV_PATH global entirely, and instead thread the path through from StateTestProvider/RPCRequest/create_default_env?

If ethereum-execution-testing is installed (possibly in a root-owned directory), there is no sane default location for the file.