[BUG] Generation logs unnecssary WARNINGs for multiple schemas for composed schema

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 (example)

Description

This logs allOf compositions with more than one schema as a WARNING, even though allOf compositions with more than one schema are what we would typically expect.

This seems to spam the first example in the debugging documentation as well.

openapi-generator version

5.3.0

Related issues/PRs

5324, sort of

Suggest a fix

Downgrade logging from WARNING to INFO or remove it. I can put the pull request together. I created the bug report in case there is more to this that I am missing.

Start in modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java at the referenced composition logging code. Reproduce generation with the first example from the debugging documentation, then confirm that an allOf composition with multiple schemas no longer emits an unnecessary WARNING.