TF-2177 Fix download attachment not working on web

Signed-off-by: dab246 <tdvu@linagora.com>
(cherry picked from commit 09cbfe5245c206670aa2191c151fd8f2ea48df3a)

lib/features/email/domain/state/download_attachment_for_web_state.dart

@@ -55,9 +55,11 @@ class DownloadAttachmentForWebSuccess extends UIState {
 
 class DownloadAttachmentForWebFailure extends FeatureFailure {
 
-  final DownloadTaskId taskId;
+  final DownloadTaskId? taskId;
 
-  DownloadAttachmentForWebFailure(this.taskId, dynamic exception) : super(exception: exception);
+  DownloadAttachmentForWebFailure({
+    this.taskId, dynamic exception
+  }) : super(exception: exception);
 
   @override
   List<Object?> get props => [taskId, ...super.props];