## 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
model = Insight
        fields = [
            "id",
            "short_id",
            "name",
            "filters",
            "dashboards",
            "description",
            "last_refresh",
            "refreshing",
            "saved",
            "tags",
            "updated_at",
            "created_by",
            "created_at",
            "last_modified_at",
        ]
        read_only_fields = ("short_id", "updated_at", "last_refresh", "refreshing")
    def create(self, validated_data: Dict, *args: Any, **kwargs: Any) -> Any:
        raise NotImplementedError()
    def to_representation(self, instance):
        representation = super().to_representation(instance)
        filters = instance.dashboard_filters()
        if not filters.get("date_from"):
            filters.update(
                {"date_from": f"-{DEFAULT_DATE_FROM_DAYS}d",}
            )
        representation["filters"] = filters
        return representation
class InsightSerializer(InsightBasicSerializer):