chore(tools): add support for large ints in Wei class

[acuarica]

🗒️ Description

This PR avoids float conversion when parsing CLI arguments of type Wei if the value is not a float number.

Using float conversion leads to conversion errors due to loss of precision when parsing large ints.

For example, if we set the CLI argument --seed-account-sweep-amount='70000 ether', we get the incorrect value 70000000000000004194304, where the expected value is 70000000000000000000000.

🔗 Related Issues or PRs

Fixes #2240.

✅ Checklist

• All: Ran fast tox checks to avoid unnecessary CI fails, see also Code Standards and Enabling Pre-commit Checks:

  uvx --with=tox-uv tox -e lint,typecheck,spellcheck,markdownlint

• All: PR title adheres to the repo standard - 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.

[LouisTsai-Csie]

Thanks for this fix, i've tested it locally and the CI is passing.