Bug Report Checklist

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

Description

additionalProperties for components from schema are completely ignored and missed in the output

openapi-generator version

6.3.0

OpenAPI declaration file content or URL

In #/components/schemas

      "PizzaDto": {
        "type": "object",
        "required": [
          "id",
          "name",
          "ingredients"
        ],
        "properties": {
          "id": {
            "type": "string",
            "format": "uuid"
          },
          "name": {
            "type": "string"
          },
          "ingredients": {
            "type": "array",
            "items": {
              "type": "object",
              "required": [
                "id"
              ],
              "properties": {
                "id": {
                  "type": "string"
                }
              }
            }
          }
        },
        "additionalProperties": {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      }

Generation Details

The schema above with default options produces

export class PizzaDto extends null<String, Array> {
    'id': string;
    'name': string;
    'ingredients': Array<PizzaDtoIngredientsInner>;
}

Please note that strange extends null and missed additional props

The expected output should be smth like this

export class PizzaDto  {
    'id': string;
    'name': string;
    'ingredients': Array<PizzaDtoIngredientsInner>;
    [key: string]: string[] | any
}

Steps to reproduce

1. Run generation with the provided schema
2. Check the model in pizzaDto.ts

Related issues/PRs

The correct generation was introduced in this PR #4698 but it's broken now.

Suggest a fix

Check the previous implementation of borrow it from typescript-angular (it does it correctly)