## 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/breakdown.py
return GroupsJoinQuery(
            self.filter, self.team_id, self.column_optimizer, using_person_on_events=self.using_person_on_events
        ).get_join_query()
    def _sessions_join_condition(self) -> Tuple[str, Dict]:
        session_query = SessionQuery(filter=self.filter, team=self.team)
        if session_query.is_used:
            query, session_params = session_query.get_query()
            return (
                f"""
                    INNER JOIN ({query}) {SessionQuery.SESSION_TABLE_ALIAS}
                    ON {SessionQuery.SESSION_TABLE_ALIAS}.$session_id = e.$session_id
                """,
                session_params,
            )
        return "", {}