Remove E2E expected bad when toast timeout is quite short

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

integration_test/scenarios/send_email_with_mark_as_important_scenario.dart

@@ -43,7 +43,6 @@ class SendEmailWithMarkAsImportantScenario extends BaseTestScenario {
     await _expectToastDisplayWithMessageMarkAsImportantIsEnabled(appLocalizations);
 
     await composerRobot.sendEmail(imagePaths);
-    await _expectSendEmailSuccessToast(appLocalizations);
     await $.pump(const Duration(seconds: 2));
 
     await _expectDisplayedEmailHasImportantFlagIcon();
@@ -63,14 +62,6 @@ class SendEmailWithMarkAsImportantScenario extends BaseTestScenario {
     );
   }
 
-  Future<void> _expectSendEmailSuccessToast(
-    AppLocalizations appLocalizations,
-  ) async {
-    await expectViewVisible(
-      $(find.text(appLocalizations.message_has_been_sent_successfully)),
-    );
-  }
-
   Future<void> _expectDisplayedEmailHasImportantFlagIcon() async {
     await expectViewVisible(
       $(EmailTileBuilder)