[typescript-angular] schema with only additionalProperties wrongly typed as Map

Description

When a schema is a object with only additionalProperties, the created model is typed as Map instead of any.

Swagger-codegen version

3.0.2

Swagger declaration file content or url

openapi: 3.0.0
info:
  title: TestApi
  version: 1.0.0
paths:
  /test:
    get:
      summary: Test
      operationId: testApi
      responses:
        "200":
          description: Ok
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Response"
components:
  schemas:
    Response:
      type: object
      additionalProperties:
        type: string

Command line used for generation

docker run --rm -v ${PWD}:/local swaggerapi/swagger-codegen-cli-v3:3.0.2 generate -i /local/swagger.yaml -l typescript-angular -o /local/ts-angular

Steps to reproduce

Suggest a fix/enhancement

The generated model is:

export type Response = Map;

and its invalid. It should be

export type Response = any;

Start with the provided OpenAPI schema in swagger.yaml and the typescript-angular generator path used by the Docker command; inspect how an object containing only additionalProperties becomes the Response model. Confirm the generated type is any rather than Map, and add or update a regression test if the generator's existing test structure supports it.