identify_task crashes if user is deleted before execution

Bug Description

Description

The identify_task Celery task does not handle the case where a user is deleted before the task executes.

If the user is removed after the task is scheduled but before execution, User.objects.get(id=user_id) raises User.DoesNotExist, causing the task to fail.

This is a common race condition in async tasks.

How to reproduce

1. Schedule the task:

   identify_task.delay(user.id)
   

2. Delete the user before the task runs: user.delete()

3. When the worker executes the task, it raises User.DoesNotExist

Expected behavior

The task should exit gracefully if the user no longer exists instead of failing.

Suggested fix

Wrap the lookup in a try/except:

try:
   user = User.objects.get(id=user_id)
except User.DoesNotExist:
   return

Debug info

- [ ] PostHog Cloud, Debug information: [please copy/paste from https://us.posthog.com/settings/project-details#variables or https://eu.posthog.com/settings/project-details#variables]
- [ ] PostHog Hobby self-hosted with `docker compose`, version/commit: [please provide]
- [ ] PostHog self-hosted with Kubernetes (deprecated, see [`Sunsetting Kubernetes support`](https://posthog.com/blog/sunsetting-helm-support-posthog)), version/commit: [please provide]

Start by locating the identify_task entry point and inspect how it looks up the user before execution. Confirm the behavior when the user has been deleted, then ensure the task exits gracefully instead of failing when the lookup cannot find a user.