## 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
"tags",
            "favorited",
            "saved",
            "last_modified_at",
            "last_modified_by",
            "is_sample",
            "effective_restriction_level",
            "effective_privilege_level",
            "timezone",
        ]
        read_only_fields = (
            "created_at",
            "created_by",
            "last_modified_at",
            "last_modified_by",
            "short_id",
            "updated_at",
            "is_sample",
            "effective_restriction_level",
            "effective_privilege_level",
            "timezone",
            "refreshing",
        )
    @lru_cache(maxsize=1)  
    def dashboard_tile_from_context(self, insight: Insight, dashboard: Optional[Dashboard]) -> Optional[DashboardTile]:
        dashboard_tile: Optional[DashboardTile] = None
        if dashboard:
            dashboard_tile = DashboardTile.objects.filter(insight=insight, dashboard=dashboard).first()
        return dashboard_tile
    def create(self, validated_data: Dict, *args: Any, **kwargs: Any) -> Insight: