TF-838 Add getMailboxState to mailbox repository

lib/features/mailbox/data/repository/mailbox_repository_impl.dart

@@ -181,4 +181,9 @@ class MailboxRepositoryImpl extends MailboxRepository {
   Future<bool> moveMailbox(AccountId accountId, MoveMailboxRequest request) {
     return mapDataSource[DataSourceType.network]!.moveMailbox(accountId, request);
   }
+
+  @override
+  Future<State?> getMailboxState() {
+    return stateDataSource.getState(StateType.mailbox);
+  }
 }

lib/features/mailbox/domain/repository/mailbox_repository.dart

@@ -32,4 +32,6 @@ abstract class MailboxRepository {
       StreamController<dartz.Either<Failure, Success>> onProgressController);
 
   Future<bool> moveMailbox(AccountId accountId, MoveMailboxRequest request);
+
+  Future<State?> getMailboxState();
 }