Merge remote-tracking branch 'origin/17575-nullable-multiple-choice-f…

…ilter' into 17575-nullable-multiple-choice-filter

# Conflicts:
#	netbox/netbox/filtersets.py

netbox/netbox/filtersets.py

@@ -180,6 +180,8 @@ def get_additional_lookups(cls, existing_filter_name, existing_filter):
                     # create the new filter with the same type because there is no guarantee the defined type
                     # is the same as the default type for the field
                     resolve_field(field, lookup_expr)  # Will raise FieldLookupError if the lookup is invalid
+                    for field_to_remove in ('choices', 'null_value'):
+                        existing_filter_extra.pop(field_to_remove, None)
                     filter_cls = type(existing_filter)
                     if lookup_expr == 'empty':
                         filter_cls = django_filters.BooleanFilter