## Is your feature request related to a problem?
See [this](https://github.com/PostHog/posthog/pull/9139/files/2754c0fd6633c806def5c328d491421ae7de0c19#diff-7f0217a57a02b6ebd709f6aa7bf43760b2d5a53069aee2b7fea27fdad1caadf1) for more info.


## Describe the solution you'd like

> This is used by django-rest-hooks, the library we use to integrate with Zapier. Specifically, this fires our Zapier integration's Triggers. However, the only trigger that actually matters is the "action_performed" one, and that has been completely delegated to the plugin server for a while. We can remove this Python cruft then, along with django-rest-hooks, but first we need to make sure action_defined and annotation_created actually are unused, and roll out an update to https://github.com/PostHog/posthog-zapier that'd remove those two completely.


## Describe alternatives you've considered

Do nothing
ee/api/test/test_hooks.py
from typing import Type, cast
from ee.api.hooks import valid_domain
from ee.api.test.base import APILicensedTest
from ee.models.hook import Hook
from posthog.test.base import ClickhouseTestMixin
class TestHooksAPI(ClickhouseTestMixin, APILicensedTest):
    def test_create_hook(self):
        data = {"target": "https://hooks.zapier.com/abcd/", "event": "action_performed"}
        response = self.client.post(f"/api/projects/{self.team.id}/hooks/", data)
        self.assertEqual(response.status_code, 201)
        hook: Type[Hook] = Hook.objects.first()
        self.assertEqual(hook.team, self.team)
        self.assertEqual(hook.target, data["target"])
        self.assertEqual(hook.event, data["event"])
        self.assertEqual(hook.resource_id, None)
        self.assertDictContainsSubset(
            {
                "id": hook.id,
                "event": data["event"],
                "target": data["target"],
                "resource_id": None,
                "team": self.team.id,
            },
            cast(dict, response.json()),
        )
    def test_create_hook_with_resource_id(self):