[BUG] Spring generator: inheritance now always requires discriminator

According to the latest OAS3.0 specification the following is a perfect fine example of inheritance:

Animal:
      type: object
      properties:
        name:
          type: string
          
    Cat: 
      allOf:
      - $ref: '#/components/schemas/Animal'
      - type: object
        properties:
          breed:
            type: string

Till version 4.3.0 it works fine, the pojo is generated as:

public class Cat extends Animal{
  String breed;
}

From version 5.0.0 I instead get:

public class Cat {
  String name;
  String breed;
}

In order to make this work in version 5.0.x I have to edit the specification like this:

Animal:
      type: object
     discriminator:
       propertyName: className
      properties:
        name:
          type: string

Is this intentional? I find it much more confusing now

Start with the Spring generator's handling of OpenAPI 3 inheritance and discriminator settings, using the specification examples in this issue as the reproduction. Compare generation behavior between versions 4.3.0 and 5.0.x; done means the discriminator-free Cat schema generates a class extending Animal without duplicating inherited properties.