When exporting data from [an insight](https://app.posthog.com/insights/oVHjTLUD), the action names weren't exported, making the CSV a little hard to follow.

As a user, I'd expect to see the same data in the export as I see in the table in-app.

<img width="1012" alt="image" src="https://user-images.githubusercontent.com/154479/166958828-9b3add76-633b-4f1d-ad2b-cf1ea2888b95.png">

posthog/api/insight.py
"""
    Simplified serializer to speed response times when loading large amounts of objects.
    """
    class Meta:
        model = Insight
        fields = [
            "id",
            "short_id",
            "name",
            "filters",
            "dashboards",
            "description",
            "last_refresh",
            "refreshing",
            "saved",
            "updated_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)
        representation["filters"] = instance.dashboard_filters()
        return representation
class InsightSerializer(TaggedItemSerializerMixin, InsightBasicSerializer):