Gajim 1.4.6: Error on logging into account

## Versions:

- OS: Linux 5.10.0-14-amd64

- GTK Version: 3.24.30

- PyGObject Version: 3.40.1

- GLib Version : 2.70.2

- python-nbxmpp Version: 3.1.0

- Gajim Version: 1.4.6

## Traceback

```

Traceback (most recent call last):

File "/gnu/store/s6s4lrjwa5yxv5cz0sc1s38vy2jsnxni-gajim-1.4.6/lib/python3.9/site-packages/gajim/gtk/controls/groupchat.py", line 285, in update_actions

joined = self.contact.is_joined

AttributeError: 'BareContact' object has no attribute 'is_joined'

```

## Steps to reproduce the problem

1. Open gajim.

2. Enter correct password.

I am running Guix on a foreign distro (Debian bullseye).

...