## 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/queries/test/test_trends.py
self._create_events()
        
        with freeze_time("2020-01-04T13:01:01Z"):
            response = ClickhouseTrends().run(
                Filter(
                    data={
                        "date_from": "-14d",
                        "breakdown": "$some_property",
                        "events": [
                            {"id": "sign up", "name": "sign up", "type": "events", "order": 0,},
                            {"id": "no events"},
                        ],
                    }
                ),
                self.team,
            )
        self.assertEqual(response[0]["label"], "sign up - value")
        self.assertEqual(response[1]["label"], "sign up - other_value")
        self.assertEqual(response[2]["label"], "no events - value")
        self.assertEqual(response[3]["label"], "no events - other_value")
        self.assertEqual(sum(response[0]["data"]), 2)
        self.assertEqual(response[0]["breakdown_value"], "value")
        self.assertEqual(sum(response[1]["data"]), 1)
        self.assertEqual(response[1]["breakdown_value"], "other_value")
    def test_breakdown_filtering_with_properties(self):