refactor: remove unused owned_show_once_timeslot_perms fixture

conftest.py

@@ -202,16 +202,6 @@ def owned_show_once_timeslot(common_user1, show, once_schedule) -> TimeSlot:
     return TimeslotFactory(schedule=once_schedule)
 
 
-@pytest.fixture
-def owned_show_once_timeslot_perms(user_with_episode_perms, show, once_schedule) -> TimeSlot:
-    """Timeslot of a once schedule for a show owned by a user with add_episode permission"""
-
-    show.owners.set([user_with_episode_perms])
-    show.save()
-
-    return TimeslotFactory(schedule=once_schedule)
-
-
 @pytest.fixture
 def show_once_timeslot(show, once_schedule) -> TimeSlot:
     return TimeslotFactory(schedule=once_schedule)