## 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
@test_with_materialized_columns(["$current_url"])
    def test_action_with_prop(self):
        _create_person(
            team_id=self.team.pk, distinct_ids=["blabla", "anonymous_id"], properties={"$some_prop": "some_val"}
        )
        sign_up_action = Action.objects.create(team=self.team, name="sign up")
        ActionStep.objects.create(
            action=sign_up_action, event="sign up", properties={"$current_url": "https://posthog.com/feedback/1234"}
        )
        with freeze_time("2020-01-02T13:01:01Z"):
            _create_event(
                team=self.team,
                event="sign up",
                distinct_id="blabla",
                properties={"$current_url": "https://posthog.com/feedback/1234"},
            )
        with freeze_time("2020-01-04T13:01:01Z"):
            action_response = Trends().run(
                Filter(
                    data={
                        "actions": [{"id": sign_up_action.id, "math": "dau"}],
                        "properties": [{"key": "$current_url", "value": "fake"}],
                    }
                ),
                self.team,
            )
        # 
        self.assertEqual(action_response[0]["count"], 0)
    @test_with_materialized_columns(["$current_url"], verify_no_jsonextract=False)
    def test_combine_all_cohort_and_icontains(self):