TF-3570 Add integration test for case mark as unread in EmailView

Signed-off-by: dab246 <tdvu@linagora.com>

lib/features/thread/presentation/mixin/base_email_item_tile.dart

@@ -208,6 +208,7 @@ mixin BaseEmailItemTile {
 
   Widget buildIconUnreadStatus() {
     return SvgPicture.asset(
+      key: const Key('unread_status_icon'),
       imagePaths.icUnreadStatus,
       width: 9,
       height: 9,

lib/features/thread/presentation/widgets/email_tile_builder.dart

@@ -1,6 +1,5 @@
 import 'package:core/presentation/extensions/color_extension.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_svg/flutter_svg.dart';
 import 'package:model/email/email_action_type.dart';
 import 'package:model/email/presentation_email.dart';
 import 'package:model/mailbox/presentation_mailbox.dart';
@@ -73,11 +72,8 @@ class EmailTileBuilder extends StatelessWidget with BaseEmailItemTile {
             if (!presentationEmail.hasRead)
               Padding(
                   padding: const EdgeInsetsDirectional.only(end: 5),
-                  child: SvgPicture.asset(
-                      imagePaths.icUnreadStatus,
-                      width: 9,
-                      height: 9,
-                      fit: BoxFit.fill)),
+                  child: buildIconUnreadStatus(),
+              ),
             Expanded(child: buildInformationSender(
               context,
               presentationEmail,