TF-4128 Separate download handling into independent class to decouple from views on web

lib/features/email/data/datasource/email_datasource.dart

@@ -1,10 +1,6 @@
 import 'dart:async';
-import 'dart:typed_data';
 
 import 'package:core/data/network/download/downloaded_response.dart';
-import 'package:core/presentation/state/failure.dart';
-import 'package:core/presentation/state/success.dart';
-import 'package:dartz/dartz.dart';
 import 'package:dio/dio.dart';
 import 'package:email_recovery/email_recovery/email_recovery_action.dart';
 import 'package:email_recovery/email_recovery/email_recovery_action_id.dart';
@@ -16,7 +12,6 @@ import 'package:jmap_dart_client/jmap/core/session/session.dart';
 import 'package:jmap_dart_client/jmap/core/user_name.dart';
 import 'package:jmap_dart_client/jmap/mail/email/email.dart';
 import 'package:model/account/account_request.dart';
-import 'package:model/download/download_task_id.dart';
 import 'package:model/email/attachment.dart';
 import 'package:model/email/mark_star_action.dart';
 import 'package:model/email/read_actions.dart';
@@ -57,13 +52,6 @@ abstract class EmailDataSource {
     ReadActions readActions,
   );
 
-  Future<List<DownloadTaskId>> downloadAttachments(
-    List<Attachment> attachments,
-    AccountId accountId,
-    String baseDownloadUrl,
-    AccountRequest accountRequest
-  );
-
   Future<DownloadedResponse> exportAttachment(
     Attachment attachment,
     AccountId accountId,
@@ -72,16 +60,6 @@ abstract class EmailDataSource {
     CancelToken cancelToken
   );
 
-  Future<Uint8List> downloadAttachmentForWeb(
-    DownloadTaskId taskId,
-    Attachment attachment,
-    AccountId accountId,
-    String baseDownloadUrl,
-    AccountRequest accountRequest,
-    StreamController<Either<Failure, Success>> onReceiveController,
-    {CancelToken? cancelToken}
-  );
-
   Future<({
     List<EmailId> emailIdsSuccess,
     Map<Id, SetError> mapErrors,
@@ -149,6 +127,7 @@ abstract class EmailDataSource {
     AccountId accountId,
     List<EmailId> emailIds,
   );
+
   Future<bool> deleteEmailPermanently(
     Session session,
     AccountId accountId,
@@ -214,17 +193,6 @@ abstract class EmailDataSource {
 
   Future<EMLPreviewer> getPreviewEMLContentInMemory(String keyStored);
 
-  Future<void> downloadAllAttachmentsForWeb(
-    AccountId accountId,
-    EmailId emailId,
-    String baseDownloadAllUrl,
-    String outputFileName,
-    AccountRequest accountRequest,
-    DownloadTaskId taskId,
-    StreamController<Either<Failure, Success>> onReceiveController,
-    {CancelToken? cancelToken}
-  );
-
   Future<DownloadedResponse> exportAllAttachments(
     AccountId accountId,
     EmailId emailId,