## Bug description

Support refreshing all dashboard items. This feature was temporarily removed because it wasn't working properly)

## Expected behavior
- All dashboard items should be properly refreshed and the `items` object in the `dashboardLogic` should contain the latest information.
- From user feedback. I expect items to be automatically refreshed every hour or so (e.g. if I'm a marketer that looks at graphs continuously during the day, or have a screen dedicated just to metrics).


## How to reproduce

1. Create a dashboard with multiple items
2. Attempt to refresh all and check the last refresh timestamp for each item (remember to uncomment relevant code)

## Environment

- [X] PostHog Cloud
- [X] self-hosted PostHog, version/commit: _please provide_

## Additional context
Follow-up to #3363

## Technical context

When refreshing all dashboard items (via `refreshAllDashboardItems()`) not all items are consistently refreshed all the time. Tested for instance with a dashboard with a couple of mixed (different type) graphs. Some items are still kept on "last refreshed 10 minutes ago".

In addition to the above, as originally reported on #3608, when calling `refreshAllDashboardItems` we update each item in their own scope, which means that the general `items` object in the upper scope logic (`dashboardLogic.js`) doesn't get updated. Not sure if we should propagate the change upwards, re-fetch everything, or just do a general refresh.

The UX problem this is causing is that the "Last refreshed" label now introduced in the dashboards gets outdated because `items` doesn't get updated. Having this object with outdated information also leads to other confusing UX issues.


#### *Thank you* for your bug report – we love squashing them!

posthog/api/test/test_dashboard.py
dashboard = Dashboard.objects.create(name="asdasd", pinned=True, team=self.team)
        response = self.client.post(
            "/api/dashboard_item/",
            {"filters": {"hello": "test"}, "dashboard": dashboard.pk, "name": "another"},
            format="json",
        ).json()
        self.client.patch(
            "/api/dashboard_item/layouts/",
            {
                "items": [
                    {
                        "id": response["id"],
                        "layouts": {
                            "lg": {"x": "0", "y": "0", "w": "6", "h": "5"},
                            "sm": {"w": "7", "h": "5", "x": "0", "y": "0", "moved": "False", "static": "False",},
                            "xs": {"x": "0", "y": "0", "w": "6", "h": "5"},
                            "xxs": {"x": "0", "y": "0", "w": "2", "h": "5"},
                        },
                    }
                ]
            },
            format="json",
        )
        items_response = self.client.get("/api/dashboard_item/{}/".format(response["id"])).json()
        self.assertTrue("lg" in items_response["layouts"])
    def test_dashboard_from_template(self):