## 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
self._create_event_count_per_user_events()
        daily_response = Trends().run(
            Filter(
                data={
                    "display": TRENDS_TABLE,
                    "breakdown": "color",
                    "events": [{"id": "viewed video", "math": "avg_count_per_actor"}],
                    "date_from": "2020-01-01",
                    "date_to": "2020-01-07",
                }
            ),
            self.team,
        )
        assert len(daily_response) == 3
        assert daily_response[0]["breakdown_value"] == "red"
        assert daily_response[1]["breakdown_value"] == "blue"
        assert daily_response[2]["breakdown_value"] == ""
        assert daily_response[0]["aggregated_value"] == 2.0  # red
        assert daily_response[1]["aggregated_value"] == 1.0  # blue
        assert daily_response[2]["aggregated_value"] == 1.0  # none
    def _create_groups(self):