[BUG][TYPESCRIPT] type array with uniqueItems generates import of Set

Created by: janKollars

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?
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Description

If a property is documented as an array of unique items the generator sets the property's type in the TypeScript file to a Set of the item type e.g. Set<string>. The problem is that Set is imported from a resource which does not exist.

import { Set } from './Set';

This line should not be generated.

openapi-generator version

5.2.1

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: OpenAPI generator Set Bug
  version: v0
servers:
  - url: http://localhost:8081
    description: Generated server url
paths:
  /test:
    get:
      responses:
        '200':
          description: OK
          content:
            TestObject:
              schema:
                $ref: '#/components/schemas/TestObject'
components:
  schemas:
    TestObject:
      type: object
      properties:
        setOfStrings:
          uniqueItems: true
          type: array
          items:
            type: string

Generation Details

No settings required.

openapi-generator generate -g typescript -i testfile-above.yaml -o wherever

Steps to reproduce

create the declaration file with the content from above locally
use the generator
inspect the file TestObject.ts

Actual result

import { Set } from './Set';
import { HttpFile } from '../http/http';

export class TestObject {
    'setOfStrings'?: Set<string>;
    ...
}

Expected result

import { HttpFile } from '../http/http';

export class TestObject {
    'setOfStrings'?: Set<string>;
    ...
}