EditDashboardView permission check broken

Traceback (most recent call last):
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/.venv/lib/python3.11/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/.venv/lib/python3.11/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/.venv/lib/python3.11/site-packages/django/views/generic/base.py", line 103, in view
    return self.dispatch(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/.venv/lib/python3.11/site-packages/django/contrib/auth/mixins.py", line 109, in dispatch
    return super().dispatch(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/.venv/lib/python3.11/site-packages/django/views/generic/base.py", line 142, in dispatch
    return handler(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/aleksis/core/views.py", line 1046, in get
    context = self.get_context_data(request, **kwargs)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/nik/AlekSIS/AlekSIS/apps/official/AlekSIS-Core/aleksis/core/views.py", line 983, in get_context_data
    or getattr(person, "is_dummy", False)
               ^^^^^^
NameError: name 'person' is not defined

added type::bug label

assigned to @yuha

created branch 773-editdashboardview-permission-check-broken to address this issue

mentioned in merge request !1162 (merged)

closed with merge request !1162 (merged)

mentioned in commit 9eaa858c