[BUG] v2 spec generation succeeds when it should throw an error

[spacether]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request

Description

[BUG] v2 spec generation succeeds when it should throw an error
per @Syuparn
and this comment:
OpenAPITools/openapi-generator#13971 (comment)

openapi-json-schema-generator version

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

Related issues/PRs

Suggest a fix

Fix: testSpecWithTooLowVersionThrowsException