Reload active room on rooms update

We need to select again the active room when we clear the room list and
we've one active room so we can reload the list of messages.

Fix https://gitlab.gnome.org/GNOME/fractal/issues/404

fractal-gtk/src/appop/room.rs

@@ -121,7 +121,7 @@ impl AppOp {
             });
             // Select active room in the sidebar
             if let Some(ref active_room) = self.active_room {
-                self.roomlist.select(active_room);
+                self.set_active_room_by_id(active_room.clone());
             }
             self.cache_rooms();
         }