## 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/trends/total_volume.py
import urllib.parse
from datetime import datetime
from typing import Any, Callable, Dict, List, Tuple
from posthog.constants import (
    MONTHLY_ACTIVE,
    NON_TIME_SERIES_DISPLAY_TYPES,
    TRENDS_CUMULATIVE,
    UNIQUE_USERS,
    WEEKLY_ACTIVE,
)
from posthog.models.entity import Entity
from posthog.models.event.sql import NULL_SQL
from posthog.models.filters import Filter
from posthog.models.team import Team
from posthog.queries.trends.sql import (
    ACTIVE_USERS_SQL,
    AGGREGATE_SQL,
    CUMULATIVE_SQL,
    SESSION_DURATION_AGGREGATE_SQL,
    SESSION_DURATION_SQL,
    VOLUME_AGGREGATE_SQL,
    VOLUME_PER_ACTOR_AGGREGATE_SQL,
    VOLUME_PER_ACTOR_SQL,
    VOLUME_SQL,
)
from posthog.queries.trends.trends_event_query import TrendsEventQuery
from posthog.queries.trends.util import (
    COUNT_PER_ACTOR_MATH_FUNCTIONS,
    PROPERTY_MATH_FUNCTIONS,
    ensure_value_is_json_serializable,