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
with freeze_time("2012-01-14T03:21:34.000Z"):
            _create_event(team=self.team, event="$pageview", distinct_id="1")
            _create_event(team=self.team, event="$pageview", distinct_id="2")
        with freeze_time("2012-01-15T04:01:34.000Z"):
            _create_event(team=self.team, event="$pageview", distinct_id="2")
            response = self.client.get(
                f"/api/projects/{self.team.id}/insights/trend.csv/?events={json.dumps([{'id': '$pageview'}])}&export_name=Pageview count&export_insight_id=test123",
            )
        lines = response.content.splitlines()
        self.assertEqual(lines[0], b"http://localhost:8000/insights/test123/", lines[0])
        self.assertEqual(
            lines[1],
            b"series,8-Jan-2012,9-Jan-2012,10-Jan-2012,11-Jan-2012,12-Jan-2012,13-Jan-2012,14-Jan-2012,15-Jan-2012",
            lines[0],
        )
        self.assertEqual(lines[2], b"$pageview,0.0,0.0,0.0,0.0,0.0,0.0,2.0,1.0")
        self.assertEqual(len(lines), 3, response.content)
    
    def test_insight_trends_allowed_if_project_open_and_org_member(self):
        self.organization_membership.level = OrganizationMembership.Level.MEMBER
        self.organization_membership.save()
        self.team.access_control = False
        self.team.save()
        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)
    def test_insight_trends_forbidden_if_project_private_and_org_member(self):