## Bug description
I added an event (that exists) to an action, and now my action hangs forever.

I added an insight viewed event

w/ filters `insight == RETENTION` and `same_retention_and_cohortizing_event = false` – this appears to have broken my action where it does not load and I cannot edit it.

Cannot reproduce this same behavior locally.


## Expected behavior
- The action loads if the schema is correct.
-  If there's erroneous data it should load and let me edit it.

## How to reproduce

1. Create an action on Posthog cloud, in our main app
2. Add 'insight viewed' with filters `insight == RETENTION` and `same_retention_and_cohortizing_event = false`
3. The action will spin forever

## Environment

- [x] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: _please provide_

## Additional context

[Sentry error](https://sentry.io/organizations/posthog/issues/2378948964/?project=1899813&referrer=slack)

Console errors 
<img width="1607" alt="Screen Shot 2021-05-03 at 5 45 39 PM" src="https://user-images.githubusercontent.com/5965891/116950024-b0d7a280-ac38-11eb-93c8-245390240532.png">
<img width="1167" alt="Screen Shot 2021-05-03 at 5 51 34 PM" src="https://user-images.githubusercontent.com/5965891/116950026-b208cf80-ac38-11eb-96e1-6a8f018f650a.png">



#### *Thank you* for your bug report – we love squashing them!

ee/clickhouse/models/action.py
if step.event == AUTOCAPTURE_EVENT:
            from ee.clickhouse.models.property import filter_element  
            el_conditions, element_params = filter_element(
                model_to_dict(step), "{}_{}{}".format(action.pk, index, prepend)
            )
            params = {**params, **element_params}
            conditions += el_conditions
        
        event_conditions, event_params = filter_event(step, "{}_{}{}".format(action.pk, index, prepend), index)
        params = {**params, **event_params}
        conditions += event_conditions
        if step.properties:
            from ee.clickhouse.models.property import parse_prop_clauses
            prop_query, prop_params = parse_prop_clauses(
                Filter(data={"properties": step.properties}).properties,
                team_id=action.team.pk if filter_by_team else None,
                prepend="action_props_{}".format(action.pk),
            )
            conditions.append(prop_query.replace("AND", "", 1))
            params = {**params, **prop_params}
        if len(conditions) > 0:
            or_queries.append(" AND ".join(conditions))
    if use_loop:
        formatted_query = "SELECT uuid FROM events WHERE {} AND team_id = %(team_id)s".format(
            ") OR uuid IN (SELECT uuid FROM events WHERE team_id = %(team_id)s AND ".join(or_queries)
        )
    else:
        formatted_query = "(({}))".format(") OR (".join(or_queries))
    return formatted_query, params
def filter_event(step: ActionStep, prepend: str = "event", index: int = 0) -> Tuple[List[str], Dict]: