Wrong schema generation of `Object[]` for OpenAPI 3.1

Schema generation for object array is broken in OpenAPI 3.1.

Create a class with an object array field and resolve the schema for it:

private Object[] objectArray;

Set a breakpoint here and inspect the schema before and after. After the call items of the ArraySchema has no more information (e.g. type = object).

The serialized schema looks like this:

          "objectArray": {
            "type": "array",
            "items": {

            }
          }

Start in modules/swagger-core/src/main/java/io/swagger/v3/core/util/AnnotationsUtils.java at the linked line, then reproduce schema resolution with a class containing an Object[] field. Inspect the ArraySchema before and after the call and compare the serialized OpenAPI 3.1 output. Done means the items schema retains its object information instead of serializing as an empty object.