feat(tests): json schema verification

[winsvega]

🗒️ Description

Pydanticfy the json schemas so we verify the quality of generated test fixtures

This is an MVP to catch what I think is the cause of bug

src/ethereum_test_fixtures/verify_format.py:28: in verify_blockchain_fixture_json
    raise Exception(
E   Exception: Error in generated blockchain test json (tests/frontier/opcodes/test_dup.py::test_dup[fork_Frontier-evm_code_type_LEGACY-blockchain_test-DUP1])[{"type":"extra_forbidden","loc":["baseFeePerGas"],"msg":"Extra inputs are not permitted","input":"0x00","url":"https://errors.pydantic.dev/2.9/v/extra_forbidden"}]

pyspecs with evmone-t8n export extra field on all forks which should not be there. perhaps this extra field leads to wrong block init in its' t8n when we blindly feeding the env section. and to a wrong state hash in my test scenarios.

so the issue is
evmone-t8n return

"currentBaseFee": "0x0",

on all forks. and we export it to the final test. when this field is only in blockheader in exported test since London

🔗 Related Issues

#940

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Added an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: All converted JSON/YML tests from ethereum/tests have been added to converted-ethereum-tests.txt.
• Tests: A PR with removal of converted JSON/YML tests from ethereum/tests have been opened.
• Tests: Included the type and version of evm t8n tool used to locally execute test cases: e.g., ref with commit hash or geth 1.13.1-stable-3f40e65.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.