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
queryset = Insight.objects.all()
    serializer_class = InsightSerializer
    permission_classes = [IsAuthenticated, ProjectMembershipNecessaryPermissions, TeamMemberAccessPermission]
    renderer_classes = tuple(api_settings.DEFAULT_RENDERER_CLASSES) + (csvrenderers.CSVRenderer,)
    filter_backends = [DjangoFilterBackend]
    filterset_fields = ["short_id", "created_by"]
    include_in_docs = True
    def get_serializer_class(self) -> Type[serializers.BaseSerializer]:
        if (self.action == "list" or self.action == "retrieve") and str_to_bool(
            self.request.query_params.get("basic", "0"),
        ):
            return InsightBasicSerializer
        return super().get_serializer_class()
    def get_queryset(self) -> QuerySet: