Add Python example to automated accessibility checks RFC

[yndajas]

See:

• https://dxw.slack.com/archives/C0151NYR5FY/p1730810930434489
• https://github.com/nationalarchives/ds-caselaw-public-ui
• e2e-tests in https://github.com/nationalarchives/ds-caselaw-public-ui/blob/main/.github/workflows/ci.yml
• https://github.com/nationalarchives/ds-caselaw-public-ui/blob/main/compose/local/e2e_tests/Dockerfile
• https://github.com/nationalarchives/ds-caselaw-public-ui/blob/main/e2e_tests/test_home_page.py

Via @jacksonj04