## Bug description

Creating a selector with an attribute isn't working at all.

`[data-attr="bla"]`

## Expected behavior

It should work

## How to reproduce

1. Create action
2. Add an attribute in the selector
3. 


## Additional context

The reason for this is that we store the attributes as `attr__data-attr` but we do not add `attr__` in the filtering. I am working on a solution.


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

posthog/models/event.py
with transaction.atomic():
            if kwargs.get("elements"):
                if kwargs.get("team"):
                    kwargs["elements_hash"] = ElementGroup.objects.create(
                        team=kwargs["team"], elements=kwargs.pop("elements")
                    ).hash
                else:
                    kwargs["elements_hash"] = ElementGroup.objects.create(
                        team_id=kwargs["team_id"], elements=kwargs.pop("elements")
                    ).hash
            event = super().create(*args, **kwargs)
            
            
            
            if not settings.ASYNC_EVENT_ACTION_MAPPING:
                should_post_webhook = False
                relations = []
                for action in event.actions:
                    relations.append(action.events.through(action_id=action.pk, event_id=event.pk))
                    if action.post_to_slack:
                        should_post_webhook = True
                Action.events.through.objects.bulk_create(relations, ignore_conflicts=True)
                team = kwargs.get("team", event.team)
                if should_post_webhook and team and team.slack_incoming_webhook:
                    celery.current_app.send_task("posthog.tasks.webhooks.post_event_to_webhook", (event.pk, site_url))
            return event
class Event(models.Model):