## 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.assertEqual(daily_response[0]["label"], "sign up - some_val")
            self.assertEqual(daily_response[1]["data"][0], 1)
            self.assertEqual(daily_response[1]["label"], "sign up - none")
            # 
            with freeze_time("2019-12-31T13:00:01Z"):
                monthly_response = Trends().run(
                    Filter(data={"interval": "day", "events": [{"id": "sign up", "math": "monthly_active"}]}),
                    self.team,
                )
            self.assertEqual(monthly_response[0]["data"][0], 3)  # 
            with freeze_time("2019-12-31T13:00:01Z"):
                weekly_response = Trends().run(
                    Filter(data={"interval": "day", "events": [{"id": "sign up", "math": "weekly_active"}]}),
                    self.team,
                )
            self.assertEqual(weekly_response[0]["data"][0], 3)  # 
            # 
            with freeze_time("2019-12-31T13:00:01Z"):
                daily_response = Trends().run(
                    Filter(
                        data={
                            "interval": "day",
                            "events": [{"id": "sign up", "math": "dau"}],
                            "breakdown": "$some_prop",
                        }
                    ),
                    self.team,
                )
    @test_with_materialized_columns(["$some_property"])
    def test_breakdown_filtering_limit(self):