Limit random seed range in tests (#7553)
`pytest-randomly` often passes a large seed value to `set_random_seed`
and causes an error
([example](https://github.com/deepspeedai/DeepSpeed/actions/runs/17620450004/job/50064585974))
```
E ValueError: Seed must be between 0 and 2**32 - 1
```
This PR limits the range of seed values by taking a modulo.
Signed-off-by: Masahiro Tanaka <mtanaka@anyscale.com>
