[JAVA] [jersey2] [jersey3] [okhttp] [native] Fix models-only build broken when schema has `anyOf` or `oneOf`

[Philzen]

Comes down to AbstractOpenApiSchema being a supportedFile, while actually oneOf- and anyOf-models depend on it to compile.

Fixing this closes #16257

A proper fix will also imply that this file really only is generated when needed – so that would close #18829

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