Change dummy queryset qualifier from "all" to "none"

[henryk]

As is, django-filter is not compatible with django-scopes. Django-scopes is an additional guardrail which prevents accidental data exposure. It replaces the default manager of a model with a specialized manager that will refuse queries, unless a scope is active, that is there is a restriction along the critical dimensions are present.

This breaks most usages of the .all() queryset. But luckily, many usages that only care about the queryset itself and not the contents can be replaced with .none().

This pull request replaces the critical all usage with none. Nothing else is changed.

Example exception fixed by this PR:

 [...]
  File "venv\Lib\site-packages\django_filters\rest_framework\backends.py", line 51, in get_filterset_class
    class AutoFilterSet(self.filterset_base):
  File "venv\Lib\site-packages\django_filters\filterset.py", line 62, in __new__
    new_class.base_filters = new_class.get_filters()
                             ^^^^^^^^^^^^^^^^^^^^^^^
  File "venv\Lib\site-packages\django_filters\filterset.py", line 340, in get_filters
    filters[filter_name] = cls.filter_for_field(
                           ^^^^^^^^^^^^^^^^^^^^^
  File "venv\Lib\site-packages\django_filters\filterset.py", line 363, in filter_for_field
    field, lookup_type = resolve_field(field, lookup_expr)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "venv\Lib\site-packages\django_filters\utils.py", line 204, in resolve_field
    query = model_field.model._default_manager.all().query
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "venv\Lib\site-packages\django_scopes\manager.py", line 94, in all
    a = a.all()
        ^^^^^^^
  File "venv\Lib\site-packages\django_scopes\manager.py", line 14, in error
    raise ScopeError("A scope on dimension(s) {} needs to be active for this query.".format(
django_scopes.exceptions.ScopeError: A scope on dimension(s) XXX needs to be active for this query.

[github-actions]

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utils.py
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