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, insight_id: Optional[int] = None, team_id: Optional[int] = None, expected_status: int = status.HTTP_200_OK
    ):
        if team_id is None:
            team_id = self.team.id
        if insight_id is None:
            url = f"/api/projects/{team_id}/insights/activity"
        else:
            url = f"/api/projects/{team_id}/insights/{insight_id}/activity"
        activity = self.client.get(url)
        self.assertEqual(activity.status_code, expected_status)
        return activity.json()
    def assert_insight_activity(self, insight_id: Optional[int], expected: List[Dict]):
        activity_response = self._get_insight_activity(insight_id)
        activity: List[Dict] = activity_response["results"]
        self.maxDiff = None
        self.assertEqual(
            activity, expected,
        )