## Bug description

If I mark an insight as a favorite (⭐) and then refresh, the insight is no longer marked as a favorite although it is (can see it in Favorites).

<img width="390" alt="image" src="https://user-images.githubusercontent.com/30181361/182802236-9ecf0531-899c-4f25-ae86-bc233cefdc2f.png">

Note that I'm in the _Favorites_ tab and that _Bug example_ is not starred.
## Environment

- [x] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: please provide

posthog/api/insight.py
renderer = csvrenderers.CSVRenderer()
            renderer.header = csvexport[0].keys()
            export = renderer.render(csvexport)
            if request.GET.get("export_insight_id"):
                export = "{}/insights/{}/\n".format(SITE_URL, request.GET["export_insight_id"]).encode() + export
            response = HttpResponse(export)
            response[
                "Content-Disposition"
            ] = 'attachment; filename="{name} ({date_from} {date_to}) from PostHog.csv"'.format(
                name=slugify(request.GET.get("export_name", "export")),
                date_from=filter.date_from.strftime("%Y-%m-%d -") if filter.date_from else "up until",
                date_to=filter.date_to.strftime("%Y-%m-%d"),
            )
            return response
        return Response({**result, "next": next})
    @cached_function
    def calculate_trends(self, request: request.Request) -> Dict[str, Any]:
        team = self.team
        filter = Filter(request=request, team=self.team)
        if filter.insight == INSIGHT_STICKINESS or filter.shown_as == TRENDS_STICKINESS:
            stickiness_filter = StickinessFilter(
                request=request, team=team, get_earliest_timestamp=get_earliest_timestamp
            )
            result = self.stickiness_query_class().run(stickiness_filter, team)
        else:
            trends_query = Trends()
            result = trends_query.run(filter, team)
        return {"result": result, "timezone": team.timezone}