## 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
CLASS_DATA_LEVEL_SETUP = False
    def test_retrieve_dashboard(self):
        dashboard = Dashboard.objects.create(
            team=self.team, name="private dashboard", created_by=self.user, tags=["deprecated"]
        )
        response = self.client.get(f"/api/dashboard/{dashboard.id}")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        response_data = response.json()
        self.assertEqual(response_data["name"], "private dashboard")
        self.assertEqual(response_data["description"], "")
        self.assertEqual(response_data["tags"], ["deprecated"])
        self.assertEqual(response_data["created_by"]["distinct_id"], self.user.distinct_id)
        self.assertEqual(response_data["created_by"]["first_name"], self.user.first_name)
        self.assertEqual(response_data["creation_mode"], "default")
    def test_create_basic_dashboard(self):
        response = self.client.post("/api/dashboard/", {"name": "My new dashboard"})
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
        response_data = response.json()
        self.assertEqual(response_data["name"], "My new dashboard")
        self.assertEqual(response_data["description"], "")
        self.assertEqual(response_data["tags"], [])
        self.assertEqual(response_data["creation_mode"], "default")
        instance = Dashboard.objects.get(id=response_data["id"])
        self.assertEqual(instance.name, "My new dashboard")
    def test_update_dashboard(self):