[typescript-rxjs][client] Unnecessary imports occurs when using allOf

Created by: tanmen

fixes #4629 (closed)

Hello. When using rxjs, a warning occurred in unused import. I tried to fix it, so please take a look if you like.

Before

// tslint:disable
/**
 * My application
 * My application
 *
 * The version of the OpenAPI document: 1.0.0
 * 
 *
 * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
 * https://openapi-generator.tech
 * Do not edit the class manually.
 */

 import {
     Box,
     Response,
 } from './';

 /**
  * @export
  * @interface BoxResponse
  */
 export interface BoxResponse extends Box, Response{
     /**
      * @type {string}
      * @memberof BoxResponse
      */
     status?: BoxResponseStatusEnum;
     /**
      * @type {number}
      * @memberof BoxResponse
      */
     id?: number;
     /**
      * @type {string}
      * @memberof BoxResponse
      */
     name?: string;
 }

 /**
  * @export
  * @enum {string}
  */
 export enum BoxResponseStatusEnum {
     Success = 'success',
     Error = 'error'
 }

After

// tslint:disable
/**
 * Myroad api
 * Myroad user api document
 *
 * The version of the OpenAPI document: 1.0.0
 * 
 *
 * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
 * https://openapi-generator.tech
 * Do not edit the class manually.
 */

import {
    Box,
    Response,
} from './';

/**
 * @type BoxesResponse
 * @export
 */
export type BoxesResponse = Box & Response;

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