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
result = serializers.SerializerMethodField()
    last_refresh = serializers.SerializerMethodField(
        read_only=True,
        help_text="""
    The datetime this insight's results were generated.
    If added to one or more dashboards the insight can be refreshed separately on each.
    Returns the appropriate last_refresh datetime for the context the insight is viewed in
    (see from_dashboard query parameter).
    """,
    )
    created_by = UserBasicSerializer(read_only=True)
    last_modified_by = UserBasicSerializer(read_only=True)
    effective_privilege_level = serializers.SerializerMethodField()
    dashboards = serializers.PrimaryKeyRelatedField(
        help_text="A dashboard ID for each of the dashboards that this insight is displayed on.",
        many=True,
        required=False,
        queryset=Dashboard.objects.filter(deleted=False),
    )
    filters_hash = serializers.CharField(
        read_only=True,
        help_text="""A hash of the filters that generate this insight.
        Used as a cache key for this result.
        A different hash will be returned if loading the insight on a dashboard that has filters.""",
    )
    class Meta: