## 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)`.

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posthog/queries/test/test_trends.py
_create_person(team_id=self.team.pk, distinct_ids=["p1"], properties={"name": "p1"})
        _create_event(team=self.team, event="$pageview", distinct_id="p1", timestamp="2020-01-04T12:00:00Z")
        with freeze_time("2020-01-04T13:01:01Z"):
            event_response = Trends().run(
                Filter(
                    data={
                        "date_from": "-14d",
                        "breakdown": json.dumps(["all"]),
                        "breakdown_type": "cohort",
                        "events": [{"id": "$pageview", "type": "events", "order": 0}],
                    }
                ),
                self.team,
            )
        self.assertEqual(event_response[0]["label"], "$pageview - all users")
        self.assertEqual(sum(event_response[0]["data"]), 1)
    @test_with_materialized_columns(person_properties=["name"], verify_no_jsonextract=False)
    def test_breakdown_by_cohort(self):