## 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.


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posthog/test/test_event_model.py
Person.objects.create(team=self.team, distinct_ids=["person1"], properties={"$browser": "Chrome"})
        Event.objects.create(event="$pageview", distinct_id="person1", team=self.team)
        action = Action.objects.create(name="pageview", team=self.team)
        ActionStep.objects.create(
            action=action, event="$pageview", properties=[{"key": "$browser", "value": "Chrome", "type": "person"}],
        )
        action.calculate_events()
        self.assertEqual(action.events.count(), 1)
    def test_empty(self):
        Person.objects.create(team=self.team, distinct_ids=["person1"], properties={"$browser": "Chrome"})
        action = Action.objects.create(name="pageview", team=self.team)
        ActionStep.objects.create(
            action=action, event="$pageview", properties=[{"key": "$browser", "value": "Chrome", "type": "person"}],
        )
        action.calculate_events()
        self.assertEqual(action.events.count(), 0)
class TestSendToSlack(BaseTest):