TF-1899 Store session as string to hive

(cherry picked from commit 2f570681d32b5b234f60f9e4d7f13e69a5bb2b31)

lib/features/session/domain/extensions/session_extensions.dart

@@ -1,4 +1,6 @@
 
+import 'dart:convert';
+
 import 'package:core/presentation/extensions/uri_extension.dart';
 import 'package:jmap_dart_client/http/converter/state_converter.dart';
 import 'package:jmap_dart_client/http/converter/user_name_converter.dart';
@@ -32,7 +34,7 @@ extension SessionExtensions on Session {
     return val;
   }
 
-  SessionHiveObj toHiveObj() => SessionHiveObj(values: toJson());
+  SessionHiveObj toHiveObj() => SessionHiveObj(value: jsonEncode(toJson()));
 
   String getQualifiedApiUrl({String? baseUrl}) {
     if (baseUrl != null) {