## 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/api/test/test_dashboard.py
dashboard = Dashboard.objects.create(
            team=self.team, name="private dashboard", created_by=self.user, creation_mode="template",
        )
        response = self.client.patch(
            f"/api/dashboard/{dashboard.id}",
            {
                "name": "dashboard new name",
                "creation_mode": "duplicate",
                "tags": ["official", "engineering"],
                "description": "Internal system metrics.",
            },
        )
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        response_data = response.json()
        self.assertEqual(response_data["name"], "dashboard new name")
        self.assertEqual(response_data["created_by"]["distinct_id"], self.user.distinct_id)
        self.assertEqual(response_data["creation_mode"], "template")
        self.assertEqual(response_data["description"], "Internal system metrics.")
        self.assertEqual(response_data["tags"], ["official", "engineering"])
        dashboard.refresh_from_db()
        self.assertEqual(dashboard.name, "dashboard new name")
        self.assertEqual(dashboard.tags, ["official", "engineering"])
    def test_create_dashboard_item(self):