## 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
if not insight.filters:
            return None
        dashboard = self.context.get("dashboard", None)
        if should_refresh(self.context["request"]):
            return synchronously_update_insight_cache(insight, dashboard)
        cache_key = insight.filters_hash
        if dashboard is not None:
            dashboard_tile = self.dashboard_tile_from_context(insight, dashboard)
            if dashboard_tile is not None:
                cache_key = dashboard_tile.filters_hash
                if cache_key is None:
                    
                    
                    generated_filters_hash = generate_insight_cache_key(insight, dashboard)
                    dashboard_tile.filters_hash = generated_filters_hash
                    dashboard_tile.save(update_fields=["filters_hash"])
                    cache_key = generated_filters_hash
        self.context.update({"filters_hash": cache_key})
        result = get_safe_cache(cache_key)
        if not result or result.get("task_id", None):
            return None
        
        return result.get("result")
    def get_timezone(self, insight: Insight):