## 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/queries/funnels/funnel_time_to_convert.py
from typing import Type
from rest_framework.exceptions import ValidationError
from ee.clickhouse.queries.funnels.base import ClickhouseFunnelBase
from ee.clickhouse.queries.funnels.funnel import ClickhouseFunnel
from posthog.constants import FUNNEL_TO_STEP
from posthog.models.filters.filter import Filter
from posthog.models.team import Team
class ClickhouseFunnelTimeToConvert(ClickhouseFunnelBase):
    def __init__(
        self, filter: Filter, team: Team, funnel_order_class: Type[ClickhouseFunnelBase] = ClickhouseFunnel
    ) -> None:
        super().__init__(filter, team)
        self.funnel_order = funnel_order_class(filter, team)
    def _format_results(self, results: list) -> dict:
        return {
            "bins": [(bin_from_seconds, person_count) for bin_from_seconds, person_count, _ in results],
            "average_conversion_time": results[0][2],
        }
    def get_query(self) -> str: