## Bug description

While exploring the onboarding/setup funnel, I found what seems to be a bug capturing events (perhaps it's an API request issue). When I send this request, the events don't get saved (checked directly on the database).

```
POST <host>/capture
```

```json
{
    "api_key": "API_KEY_HERE",
    "event": "Purchase item",
    "properties": {
        "distinct_id": "845555992929291"
    }
}
```


## Expected behavior
- Events should be correctly saved to the database. If on the onboarding flow, continue the user and complete the onboarding.
- If the request is malformed or an invalid API key is sent, I should not receive a 200 status code. _There seems to be an issue with the request and therefore the event is not saved_, however **if I add a random non-existent key as the API key (e.g. `invalid`), I still get a 200 and a 1 in the response.**  


## Reproduction environment
- Tested using the one-line Docker deploy.
```bash
doker run -t -i --rm --publish 8000:8000 -v postgres:/var/lib/postgresql posthog/posthog:preview
```
- Tested on the cloud version with the same result (please reach out privately if you want to know the account's email address).

posthog/middleware.py
response: HttpResponse = self.get_response(request)
        if request.path.split("/")[1] in [
            "decide",
            "engage",
            "track",
            "capture",
            "batch",
            "e",
            "static",
        ]:
            return response
        ip = self.extract_client_ip(request)
        if ip and any(ip_address(ip) in ip_network(block, strict=False) for block in self.ip_blocks):
            return response
        return HttpResponse(
            "Your IP is not allowed. Check your ALLOWED_IP_BLOCKS settings. If you are behind a proxy, you need to set TRUSTED_PROXIES. See https://posthog.com/docs/deployment/running-behind-proxy"
        )
class ToolbarCookieMiddleware(SessionMiddleware):