Update broadcast_arrays to return a tuple instead of a list

[vlad-perevezentsev]

This PR updates dpnp.broadcast_arrays() and dpnp.tensor.broadcast_arrays() to return a tuple instead of a list aligning their behavior with the Python Array API 2025.12 and NumPy

• X] Have you provided a meaningful PR description?
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• Have you tested your changes locally for CPU and GPU devices?
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• Have you checked performance impact of proposed changes?
• Have you added documentation for your changes, if necessary?
• Have you added your changes to the changelog?

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/pull/2944/index.html

[coveralls]

coverage: 78.251% (+0.003%) from 78.248% — return_tuple_broadcast_arrays into master

[github-actions]

Array API standard conformance tests for dpnp=0.21.0dev0=py313h509198e_70 ran successfully.
Passed: 1355
Failed: 5
Skipped: 16