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/test/test_insight.py
self.organization_membership.level = OrganizationMembership.Level.MEMBER
        self.organization_membership.save()
        self.team.access_control = True
        self.team.save()
        response = self.client.get(
            f"/api/projects/{self.team.id}/insights/trend/?events={json.dumps([{'id': '$pageview'}])}"
        )
        self.assertDictEqual(self.permission_denied_response("You don't have access to the project."), response.json())
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
    def test_insight_trends_allowed_if_project_private_and_org_member_and_project_member(self):
        self.organization_membership.level = OrganizationMembership.Level.MEMBER
        self.organization_membership.save()
        self.team.access_control = True
        self.team.save()
        self_team_membership = ExplicitTeamMembership.objects.create(
            team=self.team, parent_membership=self.organization_membership, level=ExplicitTeamMembership.Level.MEMBER
        )
        response = self.client.get(
            f"/api/projects/{self.team.id}/insights/trend/?events={json.dumps([{'id': '$pageview'}])}"
        )
        self.assertEqual(response.status_code, status.HTTP_200_OK)
    @patch("posthog.api.insight.capture_exception")
    def test_serializer(self, patch_capture_exception):