## Bug description

When calculating Trends results with an aggregated (e.g. single output, like big number) display type, WAU/MAU don't work. This is because we have an `ACTIVE_USERS_SQL` query for time series display types, but we don't have a version of this for aggregated display types. (See ZEN-1043.)

## How to reproduce

1. Create an insight with a single WAU or MAU series.
2. Switch display type to "Number".
3. Open the "Debug ClickHouse queries" modal from the command palette.
4. See `COUNT(*)` instead of `COUNT(DISTINCT person_id)`.

#### *Thank you* for your bug report – we love squashing them!

posthog/queries/test/test_trends.py
filter = Filter(
            {
                "date_from": "2020-01-01T00:00:00Z",
                "date_to": "2020-01-12T00:00:00Z",
                "events": [{"id": "$pageview", "type": "events", "order": 0}],
                "properties": [
                    {"key": "industry", "value": "finance", "type": "group", "group_type_index": 0},
                    {"key": "key", "value": "value", "type": "person"},
                ],
            },
            team=self.team,
        )
        response = Trends().run(filter, self.team)
        self.assertEqual(response[0]["count"], 1)
    @test_with_materialized_columns(
        person_properties=["key"], group_properties=[(0, "industry")], materialize_only_with_person_on_events=True
    )
    @snapshot_clickhouse_queries
    def test_breakdown_by_group_props_with_person_filter_person_on_events(self):
        self._create_groups()
        Person.objects.create(team_id=self.team.pk, distinct_ids=["person1"], properties={"key": "value"})
        _create_event(
            event="sign up",
            distinct_id="person1",
            team=self.team,
            properties={"$group_0": "org:5"},
            timestamp="2020-01-02T12:00:00Z",
            person_properties={"key": "value"},
            group0_properties={"industry": "finance"},
        )