## 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
1,  
                0,  
                0,  
                0,  
                0,  
            ],
        )
        self.assertEqual(
            response[1]["days"],
            [
                "2020-01-01 00:00:00",
                "2020-01-01 01:00:00",
                "2020-01-01 02:00:00",
                "2020-01-01 03:00:00",
                "2020-01-01 04:00:00",
                "2020-01-01 05:00:00",
                "2020-01-01 06:00:00",
                "2020-01-01 07:00:00",
                "2020-01-01 08:00:00",
                "2020-01-01 09:00:00",
                "2020-01-01 10:00:00",
                "2020-01-01 11:00:00",
                "2020-01-01 12:00:00",
                "2020-01-01 13:00:00",
                "2020-01-01 14:00:00",
                "2020-01-01 15:00:00",
                "2020-01-01 16:00:00",
                "2020-01-01 17:00:00",
                "2020-01-01 18:00:00",
                "2020-01-01 19:00:00",