This pull request fixes the following issues:

• Open API could not deduct the return type when using `Response.class` (in Rest Data Panache classic).
• For Rest Data Panache reactive, the return object for the endpoint '/get' was wrongly saying that was a single entity when is an array of entities.
• Finally, for the update and delete endpoints, the result status code was wrong (for update should be 201 and for delete 204).

Fix https://github.com/quarkusio/quarkus/issues/28786