Schedule nightly full test (#7870)
The full test workflow passed though it is still flakey
([Success](https://github.com/deepspeedai/DeepSpeed/actions/runs/22269243373)
/
[Failure](https://github.com/deepspeedai/DeepSpeed/actions/runs/22266498530))
This PR schedules a nightly run of the full test. It is launched only
when we have update since the last successful run.
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Signed-off-by: Masahiro Tanaka <mtanaka@anyscale.com>
Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
