## 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
properties={"key": "val", "$current_url": "/another/page"},
        )
        action = Action.objects.create(name="sign up", team=self.team)
        ActionStep.objects.create(
            action=action,
            event="sign up",
            url="/some/page",
            properties=[{"key": "key", "type": "event", "value": ["val"], "operator": "exact"}],
        )
        response = Trends().run(
            Filter(data={"date_from": "-14d", "actions": [{"id": action.pk, "type": "actions", "order": 0}]}),
            self.team,
        )
        self.assertEqual(response[0]["count"], 2)
    def test_trends_math_without_math_property(self):
        with self.assertRaises(ValidationError):
            Trends().run(Filter(data={"events": [{"id": "sign up", "math": "sum"}]}), self.team)
    @patch("posthog.queries.trends.trends.insight_sync_execute")
    def test_should_throw_exception(self, patch_sync_execute):
        self._create_events()
        patch_sync_execute.side_effect = Exception()
        # 
        with self.assertRaises(Exception):
            with self.settings(TEST=False, DEBUG=False):
                Trends().run(
                    Filter(data={"events": [{"id": "sign up", "name": "sign up", "type": "events", "order": 0}]}),
                    self.team,
                )
    @snapshot_clickhouse_queries
    def test_timezones_hourly(self):