[BUG][KOTLIN] Override is missing when parent entity has enum

Description

When generating polymorphic entities using OAS 3.0, child entities do not add the override keyword to the enum that is present in both, parent and child entities.

openapi-generator version

6.3.0

Generation Details

Consider having a structure like this:

{
  "openapi": "3.0.1",
  "components": {
    "schemas": {
      "ChildA": {
        "required": [
          "enum"
        ],
        "type": "object",
        "allOf": [
          {
            "$ref": "#/components/schemas/Parent"
          },
          {
            "type": "object",
            "properties": {
              "enum": {
                "$ref": "#/components/schemas/Enum",
                "default": "ChildA"
              }
            }
          }
        ]
      },
      "Parent": {
        "required": [
          "enum"
        ],
        "type": "object",
        "properties": {
          "enum": {
            "$ref": "#/components/schemas/Enum"
          },
          "discriminator": {
            "propertyName": "enum",
            "mapping": {
              "ChildA": "#/components/schemas/ChildA",
              "ChildB": "#/components/schemas/ChildB"
            }
          }
        },
        "Enum": {
          "enum": [
            "ChildA",
            "ChildB"
          ],
          "type": "string"
        }
      }
    }
  }
}

After generation we got these models:

data class ChildA (

    @Json(name = "enum")
    val enum: Enum? = null,

    @Json(name = "parentProperty")
    override val parentProperty: ParentProperty? = null

) : Parent

The enum field must have override keyword, like other parent properties have. And enum property must have default value set like this:
override val enum: Enum? = Enum.ChildA,

Start by reproducing generation with the supplied OAS 3.0 schema and compare the generated Kotlin ChildA model with the expected output. Verify that the shared enum property is marked override and receives the ChildA default value, while preserving the behavior of the other inherited properties.