## Bug description

<img width="696" alt="Screen Shot 2021-09-16 at 2 37 41 PM" src="https://user-images.githubusercontent.com/13460330/133689529-c4fffc7f-53f8-494e-b7a8-7fb656fd50e6.png">

## Expected behavior

Bars and labels always show on top of axes and gridlines.

## How to reproduce

1. https://app.posthog.com/insights?insight=FUNNELS&properties=%5B%5D&filter_test_accounts=false&events=%5B%7B%22id%22%3A%22%24pageview%22%2C%22name%22%3A%22%24pageview%22%2C%22type%22%3A%22events%22%2C%22order%22%3A0%7D%2C%7B%22id%22%3A%22%24pageview%22%2C%22name%22%3A%22%24pageview%22%2C%22type%22%3A%22events%22%2C%22order%22%3A1%7D%2C%7B%22id%22%3A%22%24pageview%22%2C%22name%22%3A%22%24pageview%22%2C%22type%22%3A%22events%22%2C%22order%22%3A2%7D%5D&actions=%5B%5D&exclusions=%5B%5D&interval=day&funnel_from_step=0&funnel_to_step=1&new_entity=%5B%5D&funnel_viz_type=time_to_convert&display=FunnelViz

## Environment

- [X] PostHog Cloud
- [X] self-hosted PostHog (ClickHouse-based), version/commit: _please provide_
- [X] self-hosted PostHog (Postgres-based, legacy), version/commit: _please provide_

## Additional context



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

ee/clickhouse/views/test/test_clickhouse_insights.py
"/api/insight/funnel/",
            {
                "insight": "funnels",
                "funnel_viz_type": "time_to_convert",
                "interval": "day",
                "date_from": "2021-06-07 00:00:00",
                "date_to": "2021-06-13 23:59:59",
                "funnel_to_step": 1,
                "funnel_window_days": 7,
                "events": [
                    {"id": "step one", "order": 0},
                    {"id": "step two", "order": 1},
                    {"id": "step three", "order": 2},
                ],
            },
        )
        self.assertEqual(response.status_code, 200)
        response_data = response.json()
        response_data.pop("last_refresh")
        self.assertEqual(
            response_data,
            {
                "is_cached": False,
                "result": {
                    "bins": [[2220.0, 2], [29080.0, 0], [55940.0, 0], [82800.0, 1]],
                    "average_conversion_time": 29540.0,
                },
            },
        )
    def test_funnel_time_to_convert_auto_bins_strict(self):