TF-3416 Handle open EML attachment in EML previewer

lib/features/email/presentation/controller/single_email_controller.dart

@@ -2016,12 +2016,16 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
     SmartDialog.dismiss();
 
     if (PlatformInfo.isWeb) {
-      HtmlUtils.openNewWindowByUrl(
+      bool isOpen = HtmlUtils.openNewWindowByUrl(
         RouteUtils.createUrlWebLocationBar(
           AppRoutes.emailEMLPreviewer,
           previewId: success.storeKey
         ).toString(),
       );
+
+      if (!isOpen) {
+        toastManager.showMessageFailure(PreviewEmailFromEmlFileFailure(CannotOpenNewWindowException()));
+      }
     }
   }
 

lib/features/email/presentation/model/eml_previewer.dart

@@ -0,0 +1,20 @@
+
+import 'package:equatable/equatable.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'eml_previewer.g.dart';
+
+@JsonSerializable(explicitToJson: true, includeIfNull: false)
+class EMLPreviewer with EquatableMixin {
+  final String title;
+  final String content;
+
+  EMLPreviewer({required this.title, required this.content});
+
+  factory EMLPreviewer.fromJson(Map<String, dynamic> json) => _$EMLPreviewerFromJson(json);
+
+  Map<String, dynamic> toJson() => _$EMLPreviewerToJson(this);
+  
+  @override
+  List<Object?> get props => [title, content];
+}