When tasks are re-submitted with the same key, `Scheduler.queued` may return stale `TaskState` objects

In `distributed/tests/test_client.py::test_threadsafe_get` we saw an assertion error during scheduling of queued tasks where a task was already forgotten even though the scheduler just tried to assign this task.

https://github.com/dask/distributed/actions/runs/4026033623/jobs/6920058827
```
File "D:\a\distributed\distributed\distributed\scheduler.py", line 4617, in stimulus_queue_slots_maybe_opened

assert qts.state == "queued", qts.state

AssertionError: forgotten
```

cc @gjoseph92