## 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/test/test_event_model.py
Person.objects.create(distinct_ids=["whatever"], team=self.team)
        action1 = Action.objects.create(team=self.team)
        ActionStep.objects.create(action=action1, selector="a.na\\\\v-link\\:b\\@ld", tag_name="a")
        event1 = Event.objects.create(
            team=self.team,
            distinct_id="whatever",
            elements=[
                Element(tag_name="span", attr_class=None, order=0),
                Element(tag_name="a", attr_class=["na\\v-link:b@ld"], order=1),
            ],
        )
        events = Event.objects.filter_by_action(action1)
        self.assertEqual(events[0], event1)
        self.assertEqual(len(events), 1)
    def test_with_class_with_escaped_slashes(self):
        Person.objects.create(distinct_ids=["whatever"], team=self.team)
        action1 = Action.objects.create(team=self.team)
        ActionStep.objects.create(action=action1, selector="a.na\\\\\\\\\\\\v-link\\:b\\@ld", tag_name="a")
        event1 = Event.objects.create(
            team=self.team,
            distinct_id="whatever",
            elements=[
                Element(tag_name="span", attr_class=None, order=0),
                Element(tag_name="a", attr_class=["na\\\\\\v-link:b@ld"], order=1),
            ],
        )
        events = Event.objects.filter_by_action(action1)
        self.assertEqual(events[0], event1)
        self.assertEqual(len(events), 1)
    def test_attributes(self):