## Bug description

When going to instance status > internal metrics and refreshing the dashboard, the loading fails

https://user-images.githubusercontent.com/148820/120655500-693c7480-c48b-11eb-8c75-6afd4c967506.mp4

## Expected behavior

It reloads successfully

## How to reproduce

See above

## Environment

- [x] PostHog Cloud
- [x] self-hosted PostHog, version/commit: latest

## Additional context

Seems the cause is that "refresh" requests data from `/api/insight/trends` vs getting it from `/api/dashboard/id` as on first load.

Relates to #3609  

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

posthog/tasks/update_cache.py
result: Optional[Union[List, Dict]] = None
    filter_dict = json.loads(payload["filter"])
    team_id = int(payload["team_id"])
    filter = get_filter(data=filter_dict, team=Team(pk=team_id))
    if cache_type == CacheType.FUNNEL:
        result = _calculate_funnel(filter, key, team_id)
    else:
        result = _calculate_by_filter(filter, key, team_id, cache_type)
    if result:
        cache.set(key, {"result": result, "type": cache_type, "last_refresh": timezone.now()}, CACHED_RESULTS_TTL)
def get_cache_type(filter: FilterType) -> CacheType:
    if filter.insight == INSIGHT_FUNNELS:
        return CacheType.FUNNEL
    elif filter.insight == INSIGHT_SESSIONS:
        return CacheType.SESSION
    elif filter.insight == INSIGHT_PATHS:
        return CacheType.PATHS
    elif filter.insight == INSIGHT_RETENTION:
        return CacheType.RETENTION
    elif (
        filter.insight == INSIGHT_TRENDS
        and isinstance(filter, StickinessFilter)
        and filter.shown_as == TRENDS_STICKINESS
    ) or filter.insight == INSIGHT_STICKINESS:
        return CacheType.STICKINESS
    else:
        return CacheType.TRENDS
def update_cached_items() -> None: