## 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": "Default", "pinned": "true"},)
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
        self.assertEqual(response.json()["name"], "Default")
        self.assertEqual(response.json()["creation_mode"], "default")
        self.assertEqual(response.json()["pinned"], True)
        
        response = self.client.get("/api/dashboard/").json()
        pk = Dashboard.objects.first().pk  
        self.assertEqual(response["results"][0]["id"], pk)  
        self.assertEqual(response["results"][0]["name"], "Default")  
        
        self.client.patch(
            f"/api/dashboard/{pk}/", {"deleted": "true"},
        )
        response = self.client.get("/api/dashboard/").json()
        self.assertEqual(len(response["results"]), 0)
    def test_dashboard_items(self):