[BUG] Inline responses without a schema.title do not generate a model

[nwcm]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• 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?
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Description

openapi-generator version

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

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