[CI] Fix Linux aarch64 nightly wheel uploads

[peterdsharpe]

Description

The aarch64 nightly saga continues (#1755, #1756, #1757).

In last night's run, aarch64 builds worked just fine on Python 3.10-3.14t.

However, uploads failed because they tried to upload to S3+PyPI, rather than just PyPI. The S3 half fails because the PyTorch org's OIDC trust policy doesn't include pytorch/tensordict (unlike vision/audio/ao etc.). Because these S3 and PyPI steps were bundled, the PyPI step never ran.

This fixes that by borrowing the upload code from the other tensordict-nightly platforms.

Side notes:

• Python 3.15/3.15t builds fail for an unrelated reason (Fix Python 3.15 smoke tests on Windows and Linux test-infra#8357 made 3.15 smoke tests resolve all runtime deps from download.pytorch.org, where pyvers isn't mirrored, I'll chase that separately). Not aarch64 specific, but aarch64 is the only platform that attempts a 3.15/3.15t build (other platforms stop at 3.14), so it's surfacing here. Not immediately critical to fix as 3.15 isn't released yet, but something to fix later.
• The upload runs with !cancelled() specifically because 3.15/3.15t is a WIP - this lets successful builds (3.10-3.14t) still publish.
• No continue-on-error on the new upload job: if uploads break again I'd rather the run go red than silently green.

Fingers crossed...

Motivation and Context

Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.
You can use the syntax close #15213 if this solves the issue #15213

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[vmoens]

Thanks
We'll dig into 3.15 later. 3.14 compatibility isn't a fully told story either so we'll need to think this through