[BUG][aspnetcore] Wrong Enum definition

Description

It creates the enum successfully. But then if there is a property that is a list of the enum, the generator tries to define the enum again.

openapi-generator version

5.3.0

OpenAPI declaration file content or url

components:
  schemas:
    Connection:
      description: Connection
      properties:
        id:
          maxLength: 80
          type: string
        name:
          maxLength: 80
          type: string
        outer_vlan_ethertypes:
          description: "The ethertype of the outer tag in hexadecimal notation."
          example:
            - "0x8100"
          items:
            default: "0x8100"
            enum:
              - "0x8100"
              - "0x88a8"
              - "0x9100"
            type: string
          type: array
      title: Connection
      type: object

Generation Details

Reproduce the ASP.NET Core generation using the OpenAPI declaration in the issue and inspect the generator's enum handling for the Connection schema. Trace why the inline array-item enum is defined again after the enum is created. Done means generation succeeds without a duplicate enum definition for this input.