[BUG] [ASPNETCORE] nullable array does not generate a nullable property

Bug Report Checklist

• [ x] Have you provided a full/minimal spec to reproduce the issue?
• [x ] Have you validated the input using an OpenAPI validator (example)?
• [x ] Have you tested with the latest master to confirm the issue still exists?
• [x ] Have you searched for related issues/PRs?
• [x ] What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

openapi-generator version

7.8.0

Description

When an array is makred as nullable in the openapi spec the generated property is NOT nullable

openapi: "3.0.0"
info:
  version: 1.0.0
  title: Swagger Petstore
servers: []
paths: {}
components:
  schemas:
    Pet:
      type: object
      properties:
        roleTypes:
          type: array
          items:
            type: string
          nullable: true

Generated Code:

        [DataMember(Name="roleTypes", EmitDefaultValue=true)]
        public List<string> RoleTypes { get; set; }

expected outcome:

        [DataMember(Name="roleTypes", EmitDefaultValue=true)]
        public List<string>? RoleTypes { get; set; }

Generation Details

openapi-generator-cli generate -i src/petstore.yaml -g aspnetcore --additional-properties nullableReferenceTypes=true,aspnetCoreVersion=8.0

Start with src/petstore.yaml and the ASP.NET Core generation command, then trace how the nullable array schema becomes the RoleTypes property. Done means nullableReferenceTypes=true generates List? for roleTypes while preserving the shown DataMember attributes; add or run the relevant generator regression coverage if available.