## 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
# 
        sign_up_action, _ = self._create_events()
        cohort = Cohort.objects.create(
            team=self.team, name="a", groups=[{"properties": [{"key": "key", "value": "value", "type": "person"}]}]
        )
        action_response = Trends().run(
            Filter(
                data={
                    "actions": [{"id": sign_up_action.id, "math": "dau"}],
                    "properties": [{"key": "$current_url", "value": "ii", "operator": "icontains"}],
                    "breakdown": [cohort.pk, "all"],
                    "breakdown_type": "cohort",
                }
            ),
            self.team,
        )
        self.assertEqual(action_response[0]["count"], 0)
    def test_person_filtering_in_cohort_in_action(self):