## 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/property.py
params = {}
    conditions = []
    if filters.get("selector"):
        or_conditions = []
        selectors = filters["selector"] if isinstance(filters["selector"], list) else [filters["selector"]]
        for idx, query in enumerate(selectors):
            selector = Selector(query, escape_slashes=False)
            key = "{}_{}_selector_regex".format(prepend, idx)
            params[key] = _create_regex(selector)
            or_conditions.append("match(elements_chain, %({})s)".format(key))
        if len(or_conditions) > 0:
            conditions.append("(" + (" OR ".join(or_conditions)) + ")")
    if filters.get("tag_name"):
        or_conditions = []
        tag_names = filters["tag_name"] if isinstance(filters["tag_name"], list) else [filters["tag_name"]]
        for idx, tag_name in enumerate(tag_names):
            key = "{}_{}_tag_name_regex".format(prepend, idx)
            params[key] = r"(^|;){}(\.|$|;|:)".format(tag_name)
            or_conditions.append("match(elements_chain, %({})s)".format(key))
        if len(or_conditions) > 0:
            conditions.append("(" + (" OR ".join(or_conditions)) + ")")
    attributes: Dict[str, List] = {}
    for key in ["href", "text"]:
        vals = filters.get(key)
        if filters.get(key):
            attributes[key] = [re.escape(vals)] if isinstance(vals, str) else [re.escape(text) for text in filters[key]]