TF-4233 Check label id is null

lib/features/labels/domain/exceptions/label_exceptions.dart

@@ -2,3 +2,8 @@ class LabelKeywordIsNull implements Exception {
   @override
   String toString() => 'Label keyword is null';
 }
+
+class LabelIdIsNull implements Exception {
+  @override
+  String toString() => 'Label id is null';
+}

lib/features/labels/presentation/extensions/handle_label_action_type_extension.dart

@@ -5,6 +5,7 @@ import 'package:jmap_dart_client/jmap/account_id.dart';
 import 'package:labels/extensions/list_label_extension.dart';
 import 'package:labels/model/label.dart';
 import 'package:tmail_ui_user/features/home/data/exceptions/session_exceptions.dart';
+import 'package:tmail_ui_user/features/labels/domain/exceptions/label_exceptions.dart';
 import 'package:tmail_ui_user/features/labels/domain/model/edit_label_request.dart';
 import 'package:tmail_ui_user/features/labels/domain/state/edit_label_state.dart';
 import 'package:tmail_ui_user/features/labels/presentation/label_controller.dart';
@@ -73,8 +74,17 @@ extension HandleLabelActionTypeExtension on LabelController {
         Stream.value(Left(EditLabelFailure(InteractorNotInitialized()))),
       );
     } else {
+      final labelId = selectedLabel.id;
+
+      if (labelId == null) {
+        consumeState(
+          Stream.value(Left(EditLabelFailure(LabelIdIsNull()))),
+        );
+        return;
+      }
+
       final labelRequest = EditLabelRequest(
-        labelId: selectedLabel.id!,
+        labelId: labelId,
         labelKeyword: selectedLabel.keyword,
         newLabel: newLabel,
       );