## 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
},
                }
            ),
            self.team,
        )
        response = sorted(response, key=lambda item: item["breakdown_value"])
        self.assertEqual(len(response), 5)
        # 
        self.assertEqual(response[0]["breakdown_value"], "test2@posthog.com")
        self.assertEqual(response[1]["breakdown_value"], "test3@posthog.com")
        self.assertEqual(response[2]["breakdown_value"], "test4@posthog.com")
        self.assertEqual(response[3]["breakdown_value"], "test5@posthog.com")
        self.assertEqual(response[4]["breakdown_value"], "test@gmail.com")
        # 
        response = Trends().run(
            Filter(
                data={
                    "date_from": "2020-01-01 00:00:00",
                    "date_to": "2020-07-01 00:00:00",
                    "breakdown": "email",
                    "breakdown_type": "person",
                    "events": [
                        {
                            "id": "sign up",
                            "name": "sign up",
                            "type": "events",
                            "order": 0,
                            "properties": {
                                "type": "AND",
                                "values": [