Use websockets to connect to blueapi

As of https://github.com/DiamondLightSource/blueapi/pull/1413, we can connect to blueapi using a web socket. In the queue worker, we should use this feature and have a websocket for each task, for the duration of the task. This means we can stop polling blueapi to check when a task is finished.

## Acceptance Criteria
- Websockets are used to connect to blueapi in the queue worker.

Start in the queue worker and trace how it currently polls blueapi to determine when each task finishes. Review the websocket support introduced in blueapi PR 1413, then verify that each task uses a websocket for its duration and that polling is no longer used.

Written by the indexing model from the issue text.