## Bug description

We've had a user create a funnel with Korean characters and 17 steps, which causes this issue:
![image](https://user-images.githubusercontent.com/1727427/120301818-8c212a00-c2cd-11eb-8b00-7ba242e4a9ab.png)

## Expected behavior

We should send requests to api/insight/funnel using POST instead of GET.

## How to reproduce

1.
2.
3.

## Environment

- [ ] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: _please provide_

## Additional context



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

ee/clickhouse/views/insights.py
from typing import Any, Dict, List
from rest_framework.decorators import action
from rest_framework.request import Request
from rest_framework.response import Response
from ee.clickhouse.queries.clickhouse_funnel import ClickhouseFunnel
from ee.clickhouse.queries.clickhouse_paths import ClickhousePaths
from ee.clickhouse.queries.clickhouse_retention import ClickhouseRetention
from ee.clickhouse.queries.clickhouse_stickiness import ClickhouseStickiness
from ee.clickhouse.queries.sessions.clickhouse_sessions import ClickhouseSessions
from ee.clickhouse.queries.trends.clickhouse_trends import ClickhouseTrends
from ee.clickhouse.queries.util import get_earliest_timestamp
from posthog.api.insight import InsightViewSet
from posthog.constants import INSIGHT_FUNNELS, INSIGHT_PATHS, INSIGHT_SESSIONS, INSIGHT_STICKINESS, TRENDS_STICKINESS
from posthog.decorators import cached_function
from posthog.models import Event
from posthog.models.filters import Filter
from posthog.models.filters.path_filter import PathFilter
from posthog.models.filters.retention_filter import RetentionFilter
from posthog.models.filters.sessions_filter import SessionsFilter
from posthog.models.filters.stickiness_filter import StickinessFilter
class ClickhouseInsightsViewSet(InsightViewSet):