Deleted tags show up in the list

Reproduction steps

1. Add a new tag in github repository online (www.github.com).
2. Run .Net core Controller.
3. Added tag show up in the Api.
4. Delete a tag in github repository online.
5. Run controller and API.
6. Deleted tag show up in API Controller.

7. _repository = new Repository("localfolderpath");
    var network = _repository.Network.Remotes.First();
    var refSpecs = new List<string>() { network.FetchRefSpecs.First().Specification };
    var fetchOptions = new FetchOptions { TagFetchMode = TagFetchMode.All };
    fetchOptions.CredentialsProvider = (_url, _user, _cred) => new DefaultCredentials();
    fetchOptions.CredentialsProvider += (_url, _user, _cred) => _userNamePasswordCredentials;
   
    Commands.Pull(_repository, new Signature(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), DateTime.Now), new PullOptions()
    {
        FetchOptions = fetchOptions,
        MergeOptions = new MergeOptions()
        {
            MergeFileFavor = MergeFileFavor.Theirs,
            CommitOnSuccess = true
        }
    });
   
    foreach (Remote remote in _repository.Network.Remotes)
    {
        Commands.Fetch(_repository, remote.Name, new string[0], fetchOptions, null);
        _repository.Network.Fetch(remote.Name, remote.FetchRefSpecs.Select(r => r.Specification), fetchOptions);
    }
   

Expected behavior

1. Deleted tags shouldn't come up when using _repository.Tags

Actual behavior

1. Deleted tags come up in _repository.Tags

Version of LibGit2Sharp (release number or SHA1)

Libgit2Sharp 0.26.2

Operating system(s) tested; .NET runtime tested

.Net Core 3.5, Microsoft Visual Studio Professional 2019 Version 16.9.0, .Net Framework 4.7.03190, Microsoft windows 10 pro.

使用所示的 Pull 和 Fetch 调用通过 LibGit2Sharp 0.26.2 重现该问题，然后检查远程标签被删除后 _repository.Tags 是如何填充的。将获取的 refs 与预期的标签列表进行比较；当已删除的远程标签不再出现在 _repository.Tags 中时即表示完成。