## 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/trends/trends_event_query.py
if self._using_person_on_events
            else PersonPropertiesMode.USING_PERSON_PROPERTIES_COLUMN,
            person_id_joined_alias=f"{self.DISTINCT_ID_TABLE_ALIAS if not self._using_person_on_events else self.EVENT_TABLE_ALIAS}.person_id",
        )
        self.params.update(prop_params)
        entity_query, entity_params = self._get_entity_query()
        self.params.update(entity_params)
        person_query, person_params = self._get_person_query()
        self.params.update(person_params)
        groups_query, groups_params = self._get_groups_query()
        self.params.update(groups_params)
        session_query, session_params = self._get_sessions_query()
        self.params.update(session_params)
        null_person_filter = (
            f"AND {self.EVENT_TABLE_ALIAS}.person_id != toUUIDOrZero('')" if self._using_person_on_events else ""
        )
        query = f"""
            SELECT {_fields} FROM events {self.EVENT_TABLE_ALIAS}
            {self._get_distinct_id_query()}
            {person_query}
            {groups_query}
            {session_query}
            WHERE team_id = %(team_id)s
            {entity_query}
            {date_query}
            {prop_query}
            {null_person_filter}
        """
        return query, self.params
    def _determine_should_join_persons(self) -> None: