chore: revert "feat: include latest build id in task responses" (#20184)

Reverts coder/coder#20181

I realized we don’t need this in the task response. When loading a task,
we already need much more workspace information, so it makes more sense
to fetch the workspace data separately instead of trying to embed all
its details into the response.

I think we can keep the task response clean and focused on the essential
information needed to list tasks. For more specific details, we can
fetch the related resources as needed. So, I’m reverting this PR.

cli/exp_task_status_test.go

@@ -193,7 +193,6 @@ STATE CHANGED  STATUS   HEALTHY  STATE  MESSAGE
   "workspace_agent_id": null,
   "workspace_agent_lifecycle": null,
   "workspace_agent_health": null,
-  "latest_build_id": null,
   "initial_prompt": "",
   "status": "running",
   "current_state": {