## 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
def test_create_elements(self):
        elements = [
            Element(tag_name="button", text="Sign up!"),
            Element(tag_name="div"),
        ]
        group1 = ElementGroup.objects.create(team=self.team, elements=elements)
        elements = list(Element.objects.all())
        self.assertEqual(elements[0].tag_name, "button")
        self.assertEqual(elements[1].tag_name, "div")
        elements = [
            Element(tag_name="button", text="Sign up!"),
            
            Element(tag_name="div", event=Event.objects.create(team=self.team)),
        ]
        group2 = ElementGroup.objects.create(team=self.team, elements=elements)
        self.assertEqual(Element.objects.count(), 2)
        self.assertEqual(group1.hash, group2.hash)
        
        team2 = Team.objects.create()
        group3 = ElementGroup.objects.create(team=team2, elements=elements)
        group3_duplicate = ElementGroup.objects.create(team_id=team2.pk, elements=elements)
        self.assertNotEqual(group2, group3)
        self.assertEqual(ElementGroup.objects.count(), 2)
class TestActions(BaseTest):