## 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
try:
            serializer = TrendSerializer(request=request)
            serializer.is_valid(raise_exception=True)
        except Exception as e:
            capture_exception(e)
        result = self.calculate_trends(request)
        filter = Filter(request=request, team=self.team)
        next = (
            format_paginated_url(request, filter.offset, BREAKDOWN_VALUES_LIMIT)
            if len(result["result"]) >= BREAKDOWN_VALUES_LIMIT
            else None
        )
        if self.request.accepted_renderer.format == "csv":
            csvexport = []
            for item in result["result"]:
                line = {"series": item["action"].get("custom_name") or item["label"]}
                for index, data in enumerate(item["data"]):
                    line[item["labels"][index]] = data
                csvexport.append(line)