## 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
if self._cohort:
            cohort_table = (
                GET_STATIC_COHORTPEOPLE_BY_COHORT_ID if self._cohort.is_static else GET_COHORTPEOPLE_BY_COHORT_ID
            )
            return (
                f"""
            INNER JOIN (
                {cohort_table}
            ) {self.COHORT_TABLE_ALIAS}
            ON {self.COHORT_TABLE_ALIAS}.person_id = person.id
            """,
                {"team_id": self._team_id, "cohort_id": self._cohort.pk},
            )
        else:
            return "", {}
    def _get_limit_offset(self) -> Tuple[str, Dict]:
        if not isinstance(self._filter, Filter):
            return "", {}
        if not (self._filter.limit or self._filter.offset):
            return "", {}
        clause = ""
        params = {}
        if self._filter.limit:
            clause += " LIMIT %(limit)s"
            params.update({"limit": self._filter.limit})
        if self._filter.offset:
            clause += " OFFSET %(offset)s"
            params.update({"offset": self._filter.offset})
        return clause, params
    def _get_search_clause(self, prepend: str = "") -> Tuple[str, Dict]: