Task visible for team admin (in overview) are no longer hidden

We had legacy code which checked single tasks in an overview for visibility to a certain user (as we used to have "private" tasks and per-task-level visibility).

Currently the visibility / accessiblity checks are already performed on the collection level and a double check does not seem to be necessary.

Furthermore team-admins which should be able to see all tasks could not see these (although allowed on index/controller) level as the view hidd them again.