## 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
import json
from django.utils import timezone
from django.utils.timezone import now
from freezegun import freeze_time
from rest_framework import status
from posthog.models import Dashboard, DashboardItem, Filter, User
from posthog.test.base import APIBaseTest
from posthog.utils import generate_cache_key
class TestDashboard(APIBaseTest):