## Bug description

The following filter fails with a 500 internal error.

![2021-02-04_12-07](https://user-images.githubusercontent.com/148820/106877644-a9f4ce80-66e1-11eb-8320-87bb213bdde2.png)


## Expected behavior

Error is shown to user about invalid regular expression.

Note no errors shown on the page as well.

## How to reproduce

1. Go to events
2. Add filter "Current URL matches regular expression ?*"
3. See infinite loading screen / error

## Environment

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

## Additional context

Note this can also happen when filtering by events.

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

ee/clickhouse/models/property.py
parsed_date_from = "AND timestamp >= '{}'".format(relative_date_parse("-7d").strftime("%Y-%m-%d 00:00:00"))
    parsed_date_to = "AND timestamp <= '{}'".format(timezone.now().strftime("%Y-%m-%d 23:59:59"))
    if value:
        return sync_execute(
            SELECT_PROP_VALUES_SQL_WITH_FILTER.format(parsed_date_from=parsed_date_from, parsed_date_to=parsed_date_to),
            {"team_id": team.pk, "key": key, "value": "%{}%".format(value)},
        )
    return sync_execute(
        SELECT_PROP_VALUES_SQL.format(parsed_date_from=parsed_date_from, parsed_date_to=parsed_date_to),
        {"team_id": team.pk, "key": key},
    )