## 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  

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posthog/tasks/update_cache.py
return getattr(importlib.import_module(module), name)
def _calculate_by_filter(filter: FilterType, key: str, team_id: int, cache_type: CacheType) -> List[Dict[str, Any]]:
    dashboard_items = DashboardItem.objects.filter(team_id=team_id, filters_hash=key)
    dashboard_items.update(refreshing=True)
    if is_clickhouse_enabled():
        insight_class_path = CH_TYPE_TO_IMPORT[cache_type]
    else:
        insight_class_path = TYPE_TO_IMPORT[cache_type]
    insight_class = import_from(insight_class_path[0], insight_class_path[1])
    result = insight_class().run(filter, Team(pk=team_id))
    dashboard_items.update(last_refresh=timezone.now(), refreshing=False)
    return result
def _calculate_funnel(filter: Filter, key: str, team_id: int) -> List[Dict[str, Any]]:
    dashboard_items = DashboardItem.objects.filter(team_id=team_id, filters_hash=key)
    dashboard_items.update(refreshing=True)
    if is_clickhouse_enabled():
        insight_class = import_from("ee.clickhouse.queries.clickhouse_funnel", "ClickhouseFunnel")
    else:
        insight_class = import_from("posthog.queries.funnel", "Funnel")
    result = insight_class(filter=filter, team=Team(pk=team_id)).run()
    dashboard_items.update(last_refresh=timezone.now(), refreshing=False)
    return result