🐛(backend) fix team accesses abilities

To compute accesses's abilities, we need to determine
which is the user's role in the team.

We opted for a subquery, which retrieves the user's role
within the team and annotate queryset's results.

The current subquery was broken, and retrieved other
users than the request's user. It led to compute accesses'
abilities based on a randomly picked user.

src/backend/core/api/viewsets.py

@@ -348,7 +348,7 @@ class TeamAccessViewSet(
             # instance for the logged-in user (we don't want to list only the team access
             # instances pointing to the logged-in user)
             user_role_query = models.TeamAccess.objects.filter(
-                team__accesses__user=self.request.user
+                user=self.request.user, team=self.kwargs["team_id"]
             ).values("role")[:1]
 
             queryset = (