## 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)`.

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posthog/queries/person_query.py
"""
    Query class responsible for joining with `person` clickhouse table
    For sake of performance, this class:
    - Tries to do as much person property filtering as possible here
    - Minimizes the amount of columns read
    """
    PERSON_PROPERTIES_ALIAS = "person_props"
    COHORT_TABLE_ALIAS = "cohort_persons"
    ALIASES = {"properties": "person_props"}
    _filter: Union[Filter, PathFilter, RetentionFilter, StickinessFilter]
    _team_id: int
    _column_optimizer: ColumnOptimizer
    _extra_fields: Set[ColumnName]
    _inner_person_properties: Optional[PropertyGroup]
    _cohort: Optional[Cohort]
    def __init__(