[BUG] Typescript-axios discriminator child-models has addition wrong self import

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 ] What's the version of OpenAPI Generator used?
• [ x ] Have you search for related issues/PRs?
• [ x ] What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

Import declaration conflicts with local declaration of Result1

import { Result1 } from './result1';
import { Result1AllOf } from './result1-all-of';
import { Result2 } from './result2';
import { ResultBase } from './result-base';

/**
 * @type Result1
 * @export
 */
export type Result1 = Result1AllOf & ResultBase;

openapi-generator version

Latest docker image from master, 5.0.0

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  version: 0.0.1
  title: TS discriminator bad imports example

paths: {}

components:
  schemas:

    Result1:
      allOf:
        - $ref: '#/components/schemas/ResultBase'
        - type: object
          properties:
            result1Property:
              type: string

    Result2:
      allOf:
        - $ref: '#/components/schemas/ResultBase'
        - type: object
          properties:
            result2Property:
              type: string

    ResultBase:
      type: object
      description: "Common fields for all results objects"
      properties:
        result_type:
          type: integer
      discriminator:
        propertyName: result_type
        mapping:
          1: "#/components/schemas/Result1"
          2: "#/components/schemas/Result2"

{
  "withSeparateModelsAndApi": true,
  "apiPackage": "api",
  "modelPackage": "models",
  "legacyDiscriminatorBehavior": false
}

ts-discriminator-import.zip

Command line used for generation

docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli generate \
-i /local/openapi.yml -g typescript-axios -o /local/generated \
-c /local/settings.json

Use the provided openapi.yml and settings.json with the documented Docker command to reproduce the generated TypeScript Axios models. Inspect the generated Result1 model and related imports, then verify that Result1 is not imported into the file where it is declared. Confirm the fix by regenerating the client and checking that the conflicting self-import and TypeScript error are gone.