PUT to `/worker/task` stuck on 409, after a 404

[dan-fernandes]

If a non-existent task is PUT to /worker/task it correctly returns a 404.

However, any valid existing plans PUT to /worker/task following this return a 409, with a stack trace.

Steps To Reproduce

Steps to reproduce the behaviour:

1. Set up system as in system tests as per the docs: https://diamondlightsource.github.io/blueapi/main/tutorials/local-auth.html
2. PUT to /worker/task via the Swagger UI, eg:

{
  "task_id": "string"
}

4. Observe 404 response
5. PUT a valid task to /tasks eg:

{
  "name": "count",
  "params": {
    "detectors": [
      "sample_stage"
    ]
  },
  "instrument_session": "cm12345-1"
}

7. PUT the outputted task_id to /worker/task
8. Obsersve 409

Acceptance Criteria

• Blueapi no longer 409's valid requests

[tpoliaw]

This is caused by duplicate tiled clients in a similar way to the callback exception issue.

• The tiled client is added to the run engine
• The task is submitted to the worker
• The worker fails to find the task and raises an exception
• The plan complete event is never sent so the client is never removed
• The next plan to run has two tiled clients involved and the second one raises the 409 Conflict

I think either #1296 or #1382 would fix this