## 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/person_query.py
fields = "id" + " ".join(
            f", argMax({column_name}, version) as {alias}" for column_name, alias in self._get_fields()
        )
        grouped_person_filters, grouped_person_params = self._get_grouped_person_filters(
            prepend=f"grouped_filters_{prepend}"
        )
        person_filters, person_params = self._get_person_filters(prepend=prepend)
        cohort_query, cohort_params = self._get_cohort_query()
        if paginate:
            limit_offset, limit_params = self._get_limit_offset()
        else:
            limit_offset = ""
            limit_params = {}
        search_clause, search_params = self._get_search_clause(prepend=prepend)
        distinct_id_clause, distinct_id_params = self._get_distinct_id_clause()
        email_clause, email_params = self._get_email_clause()
        return (
            f"""
            SELECT {fields}
            FROM person
            WHERE team_id = %(team_id)s
            AND id IN (
                SELECT id FROM person
                {cohort_query}
                WHERE team_id = %(team_id)s
                {person_filters}
            )
            GROUP BY id