__dask_keys__ and future identifiers are different

When trying to fix [dask/distributed test_client.py::test_futures_of_sorted](https://github.com/dask/distributed/actions/runs/8193868528/job/22408596167?pr=8560#step:19:3044)

> FAILED distributed/tests/test_client.py::test_futures_of_sorted - assert "('make-f63ce8128ed27f9b78bb64e3022a83de', 0)" in ""
+ where "('make-f63ce8128ed27f9b78bb64e3022a83de', 0)" = str(('make-f63ce8128ed27f9b78bb64e3022a83de', 0))
+ and "" = str()

They appear to be in order, but not the same identifiers.

Full comparison

```
(Pdb) for k, f in zip(df.__dask_keys__(), futures): print(f"{k}: {f}")
('make-4e59f4c2ced9ebff091a04c75ccf9098', 0):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 1):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 2):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 3):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 4):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 5):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 6):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 7):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 8):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 9):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 10):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 11):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 12):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 13):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 14):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 15):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 16):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 17):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 18):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 19):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 20):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 21):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 22):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 23):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 24):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 25):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 26):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 27):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 28):
('make-4e59f4c2ced9ebff091a04c75ccf9098', 29):
```

xref: https://github.com/dask/distributed/pull/8560

Start with distributed/tests/test_client.py::test_futures_of_sorted and reproduce the mismatch between df.__dask_keys__() and the returned futures, using the failure from distributed pull request 8560 as context. The issue is done when the identifiers agree and the test passes without changing the expected ordering.

Written by the indexing model from the issue text.