## Bug description

When filtering insights by active feature flags, and trying to select a single feature flag (by using a `contains` selector), events are not being correctly filter (i.e. no events are returned). This presumably happens because the `active_feature_flags` attribute is stored as an array and the operator does not work properly on CH.

## Expected behavior

Relevant events should be loaded.

## How to reproduce

1. Create an insights graph, filter by "Active feature flags" using a contain selector.

Alternatively, just open [this graph](https://app.posthog.com/insights?actions=%5B%7B%22id%22%3A1578%2C%22name%22%3A%22created%20action%22%2C%22type%22%3A%22actions%22%2C%22order%22%3A0%7D%5D&events=%5B%5D&new_entity=%5B%5D&interval=week&date_from=-90d&breakdown=false&breakdown_type&properties=%5B%7B%22key%22%3A%22%24active_feature_flags%22%2C%22value%22%3A%22actions-ux-201012%22%2C%22operator%22%3A%22icontains%22%2C%22type%22%3A%22event%22%7D%5D).

## Environment

Cloud latest version.


#### *Thank you* for your bug report – we love squashing them!

CC @timgl 

ee/clickhouse/models/cohort.py
person_query, params = format_person_query(cohort)
    person_id_query = CALCULATE_COHORT_PEOPLE_SQL.format(query=person_query)
    return person_id_query, params
def get_person_ids_by_cohort_id(team: Team, cohort_id: int):
    from ee.clickhouse.models.property import parse_prop_clauses
    filters = Filter(data={"properties": [{"key": "id", "value": cohort_id, "type": "cohort"}],})
    filter_query, filter_params = parse_prop_clauses(filters.properties, team.pk, table_name="pid")
    results = sync_execute(GET_PERSON_IDS_BY_FILTER.format(distinct_query=filter_query, query=""), filter_params)
    return [str(row[0]) for row in results]