Update create download task dialog

lib/api/client.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:cryptography/cryptography.dart';
 import 'package:dio/dio.dart';
 import 'package:eh_downloader_flutter/api/file.dart';
+import 'package:retrofit/dio.dart';
 import 'package:retrofit/retrofit.dart';
 
 import 'api_result.dart';
@@ -234,6 +235,9 @@ abstract class _EHApi {
     @Part(name: "type") String t = "download",
     @CancelRequest() CancelToken? cancel,
   });
+  @GET('/task/download_cfg')
+  Future<ApiResult<DownloadConfig>> getDefaultDownloadConfig(
+      {@CancelRequest() CancelToken? cancel});
 }
 
 class EHApi extends __EHApi {

lib/api/client.g.dart

@@ -1114,6 +1114,39 @@ class __EHApi implements _EHApi {
     return value;
   }
 
+  @override
+  Future<ApiResult<DownloadConfig>> getDefaultDownloadConfig(
+      {CancelToken? cancel}) async {
+    final _extra = <String, dynamic>{};
+    final queryParameters = <String, dynamic>{};
+    queryParameters.removeWhere((k, v) => v == null);
+    final _headers = <String, dynamic>{};
+    const Map<String, dynamic>? _data = null;
+    final _result = await _dio.fetch<Map<String, dynamic>>(
+        _setStreamType<ApiResult<DownloadConfig>>(Options(
+      method: 'GET',
+      headers: _headers,
+      extra: _extra,
+    )
+            .compose(
+              _dio.options,
+              '/task/download_cfg',
+              queryParameters: queryParameters,
+              data: _data,
+              cancelToken: cancel,
+            )
+            .copyWith(
+                baseUrl: _combineBaseUrls(
+              _dio.options.baseUrl,
+              baseUrl,
+            ))));
+    final value = ApiResult<DownloadConfig>.fromJson(
+      _result.data!,
+      (json) => DownloadConfig.fromJson(json as Map<String, dynamic>),
+    );
+    return value;
+  }
+
   RequestOptions _setStreamType<T>(RequestOptions requestOptions) {
     if (T != dynamic &&
         !(requestOptions.responseType == ResponseType.bytes ||