## 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
response = Trends().run(
                Filter(
                    data={
                        "date_from": "dStart",
                        "interval": "hour",
                        "events": [{"id": "sign up", "name": "sign up"}],
                    },
                    team=self.team,
                ),
                self.team,
            )
            self.assertEqual(
                response[0]["labels"],
                [
                    "5-Jan-2020 00:00",
                    "5-Jan-2020 01:00",
                    "5-Jan-2020 02:00",
                    "5-Jan-2020 03:00",
                    "5-Jan-2020 04:00",
                    "5-Jan-2020 05:00",
                    "5-Jan-2020 06:00",
                    "5-Jan-2020 07:00",
                    "5-Jan-2020 08:00",
                    "5-Jan-2020 09:00",
                    "5-Jan-2020 10:00",
                ],
            )
            self.assertEqual(response[0]["data"], [0.0, 0.0, 0.0, 0.0, 0, 0, 0, 1, 1, 0, 0])
    @snapshot_clickhouse_queries
    def test_timezones(self):