Sentry Issue: [POSTHOG-821](https://sentry.io/organizations/posthog/issues/3707400683/?referrer=github_integration)

Sentry is reporting that when listing session recordings loading persons is n+1

Looking at how the query works 

we 
* load person distinct ids for recordings in the list
* load the persons that have those distinct ids
* create a fict of distinct id to person
* for each of the recordings
    * look up the  person in the dict and pass them to a `PersonSerializer`
    * that looks up the person's distinct ids while choosing Person's `name`
    * (maybe only when there's no email) in order to determine the first distinct id for the person
    
 That final lookup of distinct ids is (**I think**) where the n plus 1 problem is. 
 
 For each person one at a time we go to the DB and get their distinct ids
 
 There's no foreign key from `Person` to `PersonDistinctId` so we can't utilise `select_related` here. 
 
 _maybe_ we can if we use a list serializer for Persons and then combine the two lists
 
 Some of the reports suggest 50% of the time generating the list is spent loading persons
posthog/api/test/test_session_recordings.py
Person.objects.create(
            team=self.team, distinct_ids=["user"], properties={"$some_prop": "something", "email": "bob@bob.com"}
        )
        with freeze_time("2022-01-01T12:00:00.000Z"):
            self.create_snapshot(
                "user",
                "1",
                now() - relativedelta(days=1),
                snapshot_data={"texts": ["\\ud83d\udc83\\ud83c\\udffb"]},  
            )
        response = self.client.get(f"/api/projects/{self.team.id}/session_recordings/1/snapshots")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        response_data = response.json()
        assert response_data == {
            "result": {
                "next": None,
                "snapshot_data_by_window_id": {
                    "": [
                        {
                            "texts": ["\\ud83d\udc83\\ud83c\\udffb"],
                            "timestamp": 1640952000000.0,
                            "has_full_snapshot": True,
                            "type": 2,
                            "data": {"source": 0},
                        }
                    ]
                },
            }
        }