## 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/api/test/test_dashboard.py
response = self.client.post("/api/dashboard/", {"name": "another", "use_template": "DEFAULT_APP"})
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
        self.assertGreater(DashboardItem.objects.count(), 1)
        self.assertEqual(response.json()["creation_mode"], "template")
    def test_return_cached_results_dashboard_has_filters(self):
        
        dashboard = Dashboard.objects.create(team=self.team, name="dashboard")
        filter_dict = {
            "events": [{"id": "$pageview"}],
            "properties": [{"key": "$browser", "value": "Mac OS X"}],
            "date_from": "-7d",
        }
        filter = Filter(data=filter_dict)