[BUG] Invalid warning about inline schema usage in allOf

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

Generator is logging More than one inline schema specified in allOf:. Only the first one is recognized. All others are ignored. warning, when generating Java, C# or TypeScript code from schema that is using allOf without discriminator and with more than 2 referenced schemas.

openapi-generator version

4.3.x, 5.0.0

OpenAPI declaration file content or url

Example file allOf_composition.yaml can be used to repeat this problem (schema SuperMan).
We have a use case that has 3 refs (and no inline schemas at all), which leads to the same warning.

Generation Details

    java \
        -jar openapi-generator-cli-5.0.0-beta.jar \
            generate \
            --input-spec $input_file \
            --generator-name typescript-axios \
            --output $output_folder

Steps to reproduce

1. run generator
2. check logs

Related issues/PRs

There are issues, which are discussing invalid inheritance/composition support and it seems that all of them are fixed now.
In our case generated code is correct (Java/C#/TypeScript) and all fields are there; it's a warning that is wrong.

Suggest a fix

Remove obsolete warning?

Use modules/openapi-generator/src/test/resources/3_0/allOf_composition.yaml, especially the SuperMan schema, as the reproduction input and run the shown Java CLI command with typescript-axios. Trace the warning for an allOf containing multiple referenced schemas, then confirm generation still preserves all fields without reporting an invalid inline-schema warning.